JP2001350731A - Computing device and storage medium - Google Patents

Abstract

(57) [Summary] An object of the present invention is to provide a calculation device and a storage medium that can eliminate an error that a differential value cannot be calculated at a point that can be differentiated. SOLUTION: When an input graph formula is registered, its derivative is automatically calculated by mathematical processing, and RAM6 is registered.
When an arbitrary point on the graph G1 is designated by the trace pointer P, the X coordinate value at that point is substituted into the derivative stored in the derivative memory 6b of the RAM 6. Then, the differential value is calculated, and the calculation result is saved and displayed on the display unit 4.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a computing device and a storage medium, and more particularly, to a computing device for performing a differential operation,
And a storage medium.

[0002]

2. Description of the Related Art Conventionally, a graph scientific calculator having a function of creating and displaying a graph has been used for educational sites and technical calculations of engineers. The graph scientific calculator has various built-in function calculation programs, and is capable of displaying and displaying a graph based on an input equation, displaying a graph based on an input numerical table, and the like.

[0003] It also has a program function, a statistical calculation function, a formula processing function, etc., and performs a complex repetitive operation using a program function, a data analysis using a statistical calculation function, and the like.
Processing of mathematical formulas and simplification, etc. using the mathematical formula processing function can be performed, and learning effects are exhibited not only in mathematics but also in the fields of physics and chemistry.

Some of the above-mentioned graph scientific calculators have a trace function of moving a trace pointer on a drawn graph and designating an arbitrary position on the graph. Then, a differential value at a point designated by the trace function can be obtained.

[0005] In the following, a description will be given of a case where a differential operation in a conventional graph scientific calculator cannot obtain a differential value even though it is inherently differentiable. FIG. 7 shows an example of a display screen displayed during execution of a differential operation in a conventional scientific calculator.

First, in order to set the display range of the display screen, as shown in FIG.
01 is displayed. In the window value setting screen 101, a coordinate value (Xmin, Ymin) at the lower left of the display screen and a coordinate value (Xmax, Ymax) at the upper right of the display screen can be designated. In the example of this figure, Xmin = “− 1.E. -96 (-1 x 1
0 ^-96 ) ", Xmax =" 2.E-95 (2x1
0 ⁻⁹⁵ ) ”, Ymin =“ − 1.E−48 (−1 × 1)
0 ^-48 ) ", Xmax =" 4.E-48 (4 x 10 ^-48 ) "
Is set. Note that “SCALE” represents the X coordinate and Y
This is a ratio with the coordinates, and is set to “1: 1” here.

Next, as shown in FIG. 7B, a graph-type input screen 102 is displayed to input a graph expression to be drawn (hereinafter, referred to as a graph type). An arbitrary expression can be input on the graph expression input screen 102. In the example of FIG.
"Y1 = @ X" is input.

Thereafter, when a graph drawing instruction is input, as shown in FIG. 7C, the input graph expression “Y1 = √
A graph G10 corresponding to “X” is displayed on the graph display screen 103.

When the trace function is executed on the graph display screen 103, a trace pointer P is displayed at an arbitrary point on the graph G10. When the trace pointer P is moved by operating the cursor moving keys “←”, “→”, “↑”, “↓” and the designated point is determined by operating the “EXE” key,
The X coordinate value 103b and the Y coordinate value 103c at the designated point are calculated and displayed on the graph display screen 103. Then, when an instruction to display the differential value is set in advance or an instruction to display the differential value is input, the differential value “dY / dX” at the designated point is calculated, and the calculation result is displayed.

[0010]

However, in the conventional graph scientific calculator, as shown in the example of FIG. 7 (D), the differential value is calculated although the point is originally differentiable depending on the position of the designated point. It may not be possible. In this case, “ERROR” is displayed as the calculation result. This occurs because an intermediate difference method is used as a conventional differential calculation method, and a differential value is calculated by numerical differentiation from both sides of a designated point. FIG.
Similarly, in (E) and FIG. 7 (F), the differential value becomes an error.
The following equation (1) shows a conventional differential operation equation.

[0011]

(Equation 1)

In the above example, since the graph expression is “Y = √X”, the argument of the second term “f (x−Δx)” in expression (1) becomes negative, and an error occurs in the operation. For this reason, there is a problem that an error occurs at a point that can be differentiated, and the calculation accuracy is reduced.

[0013] Even if the differential value can be calculated by the conventional graph scientific calculator, when the setting is made to display the differential value at the trace position every time the trace pointer P is moved (differential value display setting). However, since the calculation of the above equation (1) is performed every time the trace pointer P is moved, there is a problem that the tracing speed is reduced.

An object of the present invention is to provide a calculation device and a storage medium that can eliminate an error that a differential value cannot be calculated at a point that can be differentiated.

It is another object of the present invention to provide a calculation device and a storage medium capable of increasing the tracing speed when setting the differential value display.

[0016]

The present invention has the following features in order to achieve the above object. In the following description of the means, a configuration corresponding to the embodiment will be exemplified by parentheses as an example. Reference numerals and the like are reference numerals and the like in the drawings described later.

According to a first aspect of the present invention, there is provided a calculating device for performing a differential operation, wherein a derivative calculating means (for example, CPU 2 shown in FIG. 1; FIG. 3) and a differential value calculating means (for example, CPU 2 shown in FIG. 1) for calculating a differential value at the point by substituting the coordinate value of a predetermined point into the derivative calculated by the derivative calculating means. ; S15 in FIG. 4)
And characterized in that:

According to the first aspect of the present invention, there is provided a computing device for performing a differential operation, wherein a derivative of an expression to be operated is calculated by a mathematical expression process by a derivative calculating means, and the derivative value calculating means calculates the derivative of the expression. By substituting the coordinate value of a predetermined point into the derivative calculated by the derivative calculating means, a differential value at that point is calculated.

Accordingly, it is possible to eliminate an error that a differential value cannot be obtained at a point which can be differentiated, thereby improving the calculation accuracy.

According to a second aspect of the present invention, in the computing device according to the first aspect, the derivative calculating means includes:
Storage means for automatically calculating and storing the derivative when registering the expression to be operated on (for example, S1 to S1 in FIG. 3)
It is effective to provide S3).

According to the second aspect of the present invention, the derivative is automatically calculated and stored at the time of registering the expression to be operated by the storage means. The differential value can be calculated by the same operation procedure as in the related art without having to input an instruction for calculating the differential value.
Further, since the differential value is calculated based on the stored derivative, it is not necessary to calculate the derivative every time the derivative point is changed, and the calculation speed at the time of repeatedly performing the differential calculation can be improved.

According to a third aspect of the present invention, there is provided a calculating device for executing a differential operation, wherein it is determined whether or not a differential value at a predetermined point of an expression to be operated can be calculated by a two-sided differential (expression (1)). Determining means (for example, the CPU shown in FIG. 1)
2; S36 to S37 in FIG. 6), and when the discriminating means determines that the differential value cannot be calculated by the two-sided differential, the differential value is calculated by the one-sided differential (formula (2) or (3)). Calculation means (for example, the CPU shown in FIG. 1)
2; S38 to S40 in FIG. 6).

According to a third aspect of the present invention, there is provided a calculating device for performing a differential operation, wherein the determining means determines whether or not the differential value at a predetermined point of the expression to be operated can be calculated by the two-sided differential. If it is determined that the differential value cannot be calculated by the two-sided differentiation, the calculating means calculates the differential value by the one-sided differentiation.

Therefore, even when the differential value cannot be calculated by the two-sided differential (central difference method), the differential value can be obtained by the one-sided differential. That is, it is possible to eliminate an error that a differential value cannot be obtained at a point that can be differentiated, thereby improving the calculation accuracy.

According to a fourth aspect of the present invention, in the computing device according to any one of the first to third aspects, a graph drawing means (for example, a figure drawing means) for drawing a graph corresponding to the expression to be operated on. 3 (S4) and a trace designating unit (for example, S5 in FIG. 3) for designating an arbitrary point by tracing on the graph drawn by the graph drawing unit.
It is effective that the predetermined point is a point specified by the trace specifying means.

According to the fourth aspect of the present invention, the graph drawing means draws a graph corresponding to the expression to be operated on, and the trace designating means allows an arbitrary point to be traced on the drawn graph. When specified, the differential value at the point specified by the trace specifying means is calculated, so that the differential point can be easily specified by tracing to calculate the differential value. When the derivative calculated by the mathematical processing is stored, it is not necessary to change the derivative each time the derivative point is moved by tracing, and the tracing speed at the time of setting the differential value display can be improved.

[0027]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing an embodiment of a computer according to the present invention.

[First Embodiment] In the first embodiment, an example will be described in which the present invention is applied to a calculation device 1 such as a small electronic calculator (scientific calculator) equipped with a mathematical formula processing function. It shall be.

First, the configuration will be described. FIG. 1 is a block diagram showing a configuration of a computing device 1 according to the present invention. As shown in FIG. 1, the computing device 1 includes a CPU (Central Processing Uniform).
t) 2, input unit 3, display unit 4, display drive circuit 5, RAM
(Random Access Memory) 6, ROM (Read Only Memo)
ry) 7, a storage device 8, and a storage medium 9.

The CPU 2 reads a predetermined program from the ROM 7 or the storage device 8 based on an instruction input through the input unit 3 and temporarily stores the read program in the RAM 6, executes various processes based on the program, and executes various processes based on the program. Centralized control of each unit. That is, the CPU 2 executes various processes based on the read predetermined program, stores the process results in the work memory in the RAM 6, generates display data by the display drive circuit 5, and causes the display unit 4 to display the display data. . Further, based on an instruction input through the input unit 3, the processing result is stored in the storage medium 9 via the storage device 8.

When performing a function operation in the computing device 1 of the present embodiment, the CPU 2 executes a graph-type registration process (to be described later) based on a graph-type registration process program stored in the ROM 7 or the storage device 8 (see FIG. 3). ) Is executed, and when an instruction to execute the trace function is input, a trace process (see FIG. 4) described later is executed in accordance with the trace processing program.

In the graph type registration process (see FIG. 3),
The CPU 2 receives an input of a graph expression to be drawn (hereinafter, referred to as a graph expression), and when registering the input graph expression, obtains a derivative of the graph expression by mathematical processing, and stores a graph expression memory in the RAM 6. In addition to storing the graph formula in 6a, the calculated derivative is stored in the derivative memory 6b of the RAM 6. Then, a graph G1 corresponding to the input graph expression is drawn, and when a trace execution instruction is input, the process proceeds to a trace process.

In the trace processing (see FIG. 4), the CP
U2 obtains the X coordinate value and the Y coordinate value of the position indicated by the trace pointer P, further calls a derivative stored in the derivative memory 6b of the RAM 6, and substitutes the X coordinate value to specify the trace. The differential value at the specified point is calculated, stored in the differential value memory 6c of the RAM 6, and displayed on the display unit 4.

The input unit 3 includes numerical keys, character keys, data input keys composed of various operation keys, cursor movement keys "←", "→", which are operated when moving the cursor and the trace pointer P. "↑", "↓", "EXE" key operated to confirm selection or execute calculation, trace key operated to start execution of trace function, end or stop processing being executed It is composed of various key groups such as “ESC” key operated when
A signal for pressing the pressed key is output to the CPU 2.

The display unit 4 is a liquid crystal display (LCD).
play), and performs various displays based on a drive signal input from the display drive circuit 5. Display drive circuit 5
Generates a drive signal based on display data input from the CPU 2 and controls display of the display unit 4.

FIG. 2 is a diagram showing a configuration of a memory area set in the RAM 6. The RAM 6 stores an input graph formula as shown in FIG. 2, in addition to a work memory for temporarily storing an application program, an input instruction, input data, a processing result, and the like designated in the computer 1 of the present invention. It has various memory areas such as a graph-type memory 6a, a derivative memory 6b for storing derivatives calculated by mathematical processing, and a differential value memory 6c for storing calculated differential values.

The ROM 7 stores a basic program corresponding to the computer 1 according to the present invention and a plurality of application programs corresponding to the basic program.
That is, an initial display program, a menu selection program executed when the power of the computing device 1 is turned on,
In addition to basic programs that do not need to be rewritten, such as various function calculation programs, statistical calculation processing programs, and graph drawing programs, processing programs to be executed in the calculation device 1 of the present invention are stored.

The storage device 8 has a storage medium 9 in which programs, data and the like are stored in advance, and this storage medium 9 is constituted by a magnetic or optical storage medium or a semiconductor memory. The storage medium 9 is fixedly provided in the storage device 8 or is detachably mounted. The storage medium 9 includes the basic program and application programs corresponding to various processes corresponding to the computing device 1. And data processed by the various processing programs.

A part or all of the programs, data, and the like stored in the storage medium 9 are transmitted from a transmission control unit (not shown) from another device such as a server or a client via a transmission medium such as a network line. It may be configured to receive and store, and the storage medium 9 may be a storage medium of a server constructed on a network. Further, the program may be transmitted to a server or a client via a transmission medium such as a network line and installed in these devices.

Next, the operation of the first embodiment will be described. FIG. 3 is a flowchart illustrating the graph type registration process, FIG. 4 is a flowchart illustrating the trace process, and FIG. 5 is a specific example of a display screen displayed on the display unit 4 in the graph type registration process and the trace process. is there.

Here, a program for realizing each function included in these flowcharts is stored in the form of a readable program code in the ROM 7 or the storage medium 9.
, And the CPU 2 sequentially executes the operation according to the program code. Further, the CPU 2 can also sequentially execute the operation according to the above-described program code transmitted via the transmission medium. That is, an operation specific to this embodiment can be executed using a program / data externally supplied via a transmission medium in addition to the storage medium 9.

First, when a graph drawing function is selected on a menu screen (not shown) and an execution instruction is input,
The CPU 2 displays a window value setting screen 41 as shown in FIG. 5A on the display unit 4 and accepts the setting of the size (lower left coordinates and upper right coordinates) of the display screen as in the conventional case.
In the example of this figure, Xmin = “− 1.E−96” (−1 ×
10 ⁻⁹⁶ ), Xmax = “2.E−95” (2 × 1
0 ⁻⁹⁵ ), Ymin = “− 1.E−48” (−1 × 1)
0 ^-48), Xmax = "4.e-48" (4 × 10 ^-48) is set.

Next, in order to input a graph formula, a graph formula input screen 42 as shown in FIG. An arbitrary expression can be input on the graph expression input screen 42. In this example, it is assumed that "Y1 = @ X" is input.

As described above, when a graph formula is input and an instruction to register is input, first, the CPU 2 calculates a derivative of the graph formula "Y = $ X" by mathematical processing (step S1). Here, the derivative "Y '= 1 / 2√"
X ”is calculated. Then, the graph expression “Y = √X” is represented by R
The data is stored in the graph memory 6a of the AM 6 (step S
Along with 2), the calculated derivative "Y '= 1/2 @ X" is stored in the derivative memory 6b (step S3).

Thereafter, when a graph drawing instruction is input,
The CPU 2 generates a graph G1 corresponding to the graph expression as in the related art.
Is displayed on the graph display screen 43 as shown in FIG. 5C (step S4). The size of the graph display screen 43 is the size set on the window value setting screen 41. In FIG. 5C, 43x indicates the X axis, and 43y indicates the Y axis.

When a trace execution instruction is input on the graph display screen 43 (step S5; Yes), the CPU 2 displays a trace pointer P at an arbitrary point on the graph G1 and shifts to trace processing.

In the trace processing as shown in FIG.
When the trace pointer P is the cursor movement key "←",
When moved by "→", "↑", "↓",
The CPU 2 calculates an X coordinate value 43b for the point indicated by the trace pointer P (step S10), and further calculates a Y coordinate value 43c from the X coordinate value 43b based on a graph formula (step S11), as in the related art. .

At this time, if an error occurs (step S
12; Yes), an error message is displayed, and the process ends. If no error occurs (step S1)
2; No), the calculated X coordinate value 43b and Y coordinate value 43
c is displayed on the graph display screen 43 (step S1).
3).

Thereafter, the CPU 2 determines whether or not the setting for displaying the differential value (differential value display setting) has been made.
If the setting for displaying the differential value has been made (step S14; On), the X coordinate value is substituted for the derivative "Y '= 1/2 @ X" stored in the derivative memory 6b of the RAM 6. To calculate the differential value 43d (step S1).
5). Then, the calculated differential value 43d is saved in the differential value memory 6c of the RAM 6 and displayed on the graph display screen 43 (step S16; FIG. 5D).

FIG. 5D shows an example of a graph display screen 43 displaying the differential value at a traced point by the computing device 1 of the present embodiment. In this example, the X coordinate value 43b “X = 5.E−97 (5 × 10 ⁻⁹⁷ )”, Y
The coordinate value 43c “Y = 7.0710678E-49 (7.
0710678 × 10 ⁻⁴⁹ ) ”, the differential value 43d is calculated as“ dY / dX = 7.071 ”.
0E47 (7.0710 × 10 ⁴⁷ ) ”is calculated and displayed.

As described above, when registering the input graph formula, the calculation device 1 of the present embodiment automatically calculates its derivative by a mathematical process and registers it in the RAM 6.
When an arbitrary point on the graph G1 is designated by the trace pointer P, the X coordinate value at that point is substituted into the derivative stored in the derivative memory 6b of the RAM 6. Then, the differential value is calculated, and the calculation result is saved in the RAM 6 and displayed on the display unit 4.

Therefore, the derivative is calculated in advance by mathematical processing instead of the central difference method, and the differential value is calculated by substituting the X coordinate value of the designated point. Can be eliminated, and the calculation accuracy can be improved. Further, since the derivative is automatically calculated and stored in the RAM 6 at the time of registering the graph formula, there is no need to input an instruction to calculate the derivative by mathematical processing, and the user can perform the same operation procedure as before. Differential values can be calculated. In addition, when the differential value display setting is made at the time of tracing, the differential value at the point indicated by the trace pointer P is calculated and displayed in advance based on the stored derivative. There is no need to calculate the derivative every time the movement is performed, so that the calculation speed is improved and the tracing speed is also improved.

[Second Embodiment] In the first embodiment, the calculation apparatus 1 having a mathematical processing function has been described. However, in the second embodiment, calculation having no mathematical processing function is performed. The device 1 will be described.

The configuration of the computing device 1 according to the second embodiment is the same as that of the computing device 1 according to the first embodiment except that it does not have a mathematical formula processing function. A detailed description will be omitted, and the same components will be described with the same reference numerals. Hereinafter, the operation of the computing device 1 according to the second embodiment will be described.

FIG. 6 is a flow chart for explaining the trace processing in the second embodiment.

First, when a graph drawing function is selected on a menu screen (not shown) and an execution instruction is input,
The CPU 2 displays a window value setting screen 41 as shown in FIG. 5A on the display unit 4 and accepts the setting of the size (lower left coordinates and upper right coordinates) of the display screen as in the conventional case.
Since a specific example has been described in the first embodiment, the description is omitted.

Next, in order to input a graph formula, a graph formula input screen 42 as shown in FIG. As a specific example, similarly to the first embodiment, “Y
1 = と す る X ”is input.

When the graph expression is input and the registration instruction is input in this way, unlike the first embodiment, the graph expression "Y = $ X" is stored in the graph expression memory 6 of the RAM 6.
Stored in a.

Thereafter, when a graph drawing instruction is input,
The CPU 2 displays a graph G1 corresponding to the input graph formula as shown in FIG.
3. Draw on top.

When a trace execution instruction is input on the graph display screen 43, the CPU 2 displays a trace pointer P at an arbitrary point on the graph G1 and proceeds to the trace processing shown in FIG.

In the trace processing, the trace pointer P is moved by the cursor movement keys "←", "→", "↑", "↓".
The CPU 2 calculates the X coordinate value 43b for the point indicated by the trace pointer P (step S31), as in the conventional case, and further calculates the Y coordinate value from the X coordinate value 43b based on a graph formula. 43c is calculated (step S32).

If an error occurs at this time (step S
33; Yes), an error code is set (step S42), and the process ends. If no error occurs (Step S33; No), the calculated X coordinate value 43b and Y coordinate value 43c are displayed on the graph display screen 43 (Step S34; see FIG. 5D).

Thereafter, the CPU 2 determines whether or not the setting for displaying the differential value (differential value display setting) has been made.
If the setting for displaying the differential value has been made (Step S35; On), first, a two-sided differential operation (central difference method) is executed using the point designated by the trace pointer P as a differential point (Step S36). The two-sided differential operation is executed based on the following equation (1), similarly to the conventional differential operation.

[0064]

(Equation 2)

The CPU 2 determines whether or not an error has occurred in the two-sided differential operation in step S36. If the error has not occurred and the differential value can be calculated (step S3).
7; Yes), the calculated differential value is saved in the differential value memory 6c of the RAM 6, and displayed on the graph display screen 43 (step S43).

If an error occurs in the two-sided differential operation in step S36 and the differential value cannot be calculated (step S37; No), then the differential value is calculated by one-sided differentiation from the left side of the differential point (step S38). One-sided differentiation from the left side of the differentiation point is obtained based on the following equation (2).

[0067]

(Equation 3)

If an error occurs in the one-sided differentiation operation in step S38 and the differentiation result cannot be obtained (step S39; No), then a differential value is calculated by one-sided differentiation from the right side of the differentiation point (step S40). . The one-sided differential from the right side of the differential point is obtained based on the following equation (3).

[0069]

(Equation 4)

If an error occurs in either of the two-sided differentiation (Equation (1)) or one-sided differentiation (Equation (2) or Equation (3)) and the differential value cannot be calculated (step S41;
Yes), set an error code (step S4)
3), end the process.

If the differential value can be calculated in one of the two-sided differential operation in step S36, the one-side (left) differential operation in step S38, and the one-side (right) differential operation in step S40, the calculated differential value 43d is calculated. Is saved in the differential value memory 6c of the RAM 6 and displayed on the graph display screen 43 (step S
43; see FIG. 5 (D)).

As described above, when an arbitrary point on the graph G1 is indicated by the trace pointer P, the calculation device 1 obtains the X coordinate value at that point and calculates the X-coordinate value based on the above equation (1). Execute If the calculation of the two-sided differentiation is not possible, the one-sided differentiation from the left side of the differentiation point is executed based on the above equation (2). If the one-sided differential operation cannot be performed from the left side of the differential point,
Based on the above equation (3), one-sided differentiation from the right side of the differentiation point is executed. Two-sided or one-sided differential (right or left)
When the differential value is calculated by any one of the above, the calculated differential value is saved in the RAM 6 and displayed on the display unit 4.

Therefore, it is determined whether or not the differential operation can be performed by the central difference method (two-sided differential). If the differential operation cannot be performed, the differential value is calculated by one-sided differential. Differentiation can be obtained by differentiation. That is, it is possible to eliminate an error that a differential value cannot be obtained at a point that can be differentiated, thereby improving the calculation accuracy.

In the second embodiment, when an error occurs in the two-sided differential, the differential value is obtained by the one-sided differential. However, the differential value of “△ X” in the differential equations (1) to (3) is obtained. If the value is set to a small value, the occurrence of errors during the differential operation can be reduced, and the operation speed and the operation accuracy can be further improved.

In the above-described first and second embodiments, the differential operation at the time of executing the trace processing of the graph corresponding to the graph expression has been exemplified. However, the present invention is not limited to this. Of course, it is also applicable to the differential operation of. In the case of a normal differential operation, in the first embodiment, when registering an input expression, the value of a derivative is obtained and stored in the RAM 6, and when the coordinate value of the differential point is input, RAM of X coordinate value of differential point
Substituting into the derivative stored in 6 to obtain a differential value.
In the second embodiment, when an equation and a differential point are input, it is checked whether a differential value can be calculated by performing a two-sided differentiation at the differential point. If the differential value cannot be calculated, then a one-sided differential operation from the left side is performed. And if a differential value cannot be calculated, a one-sided differential operation from the right side is performed.

Further, in the first and second embodiments, the expression to be operated is described as being input from the input unit 3, but the present invention is not limited to this. The data may be read from the ROM 7 or may be transmitted from outside via a communication line.

[0077]

According to the first and fifth aspects of the present invention, it is possible to eliminate the error that a differential value cannot be obtained at a point that can be differentiated, thereby improving the calculation accuracy.

According to the second aspect of the present invention, the derivative is automatically calculated and stored by the storage means when the expression to be operated is registered. There is no need to input a calculation instruction, and the differential value can be calculated by the same operation procedure as in the related art. Further, since the differential value is calculated based on the stored derivative, it is not necessary to calculate the derivative every time the derivative point is changed, and the calculation speed at the time of repeatedly performing the differential calculation can be improved.

According to the third and sixth aspects of the present invention, even when the differential value cannot be calculated by the two-sided differential (central difference method), the differential value can be obtained by the one-sided differential. That is, it is possible to eliminate an error that a differential value cannot be obtained at a point that can be differentiated, thereby improving the calculation accuracy.

According to the fourth aspect of the present invention, the differential value can be calculated by easily specifying the differential point by tracing. In addition, when the derivative calculated by the mathematical processing is stored, it is not necessary to change the derivative every time the differential point is moved by tracing, so that the tracing speed can be improved.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a computing device 1 according to the present invention.

FIG. 2 is a diagram showing a configuration of a memory area set in a RAM 6;

FIG. 3 is a flowchart illustrating a graph type registration process.

FIG. 4 is a flowchart illustrating a trace process according to the first embodiment.

FIG. 5 is a specific example of a display screen displayed on a display unit 4 in a graph type registration process and a trace process.

FIG. 6 is a flowchart illustrating a trace process according to the second embodiment.

FIG. 7 is an example of a display screen displayed during execution of a differential operation in a conventional scientific calculator.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Computing device 2 CPU 3 Input part 4 Display part 41 Window value setting screen 42 Graph type input screen 43 Graph display screen 43a Graph type 43b X coordinate value of trace pointer 43c Y coordinate value of trace pointer 43d Derivative value 43x X coordinate 43y Y Coordinate G1 Graph 5 Display drive circuit 6 RAM 6a Graphical memory 6b Derivative memory 6c Differential value memory 7 ROM 8 Storage device 9 Storage medium

Claims (6)

[Claims] 1. A calculating device for performing a differential operation, comprising: a derivative calculating means for calculating a derivative of an expression to be operated on by mathematical processing; and a derivative calculated by the derivative calculating means. A differential value calculating means for calculating a differential value at the point by substituting the coordinate value of the point. 2. The calculation according to claim 1, wherein said derivative calculating means includes a storage means for automatically calculating and storing the derivative when registering the expression to be operated on. apparatus. 3. A computing device for performing a differential operation, comprising: a discriminating means for discriminating whether or not a differential value at a predetermined point of an expression to be computed can be calculated by a two-sided differentiation; A calculating means for calculating the differential value by one-sided differentiation when it is determined that the differential value cannot be calculated by the calculation device. 4. A graph drawing means for drawing a graph corresponding to the expression to be operated, and trace specifying means for specifying an arbitrary point by tracing on the graph drawn by the graph drawing means. 4. The computing device according to claim 1, wherein the predetermined point is a point specified by the trace specifying unit. 5. A storage medium storing a computer-executable program, wherein a computer-executable program code for performing a differential operation and a derivative of an expression to be operated are calculated by mathematical processing. Computer-executable program code, and computer-executable program code for calculating a differential value at a point by substituting a coordinate value of a predetermined point into the calculated derivative. A storage medium storing a program. 6. A storage medium storing a computer-executable program, comprising: a computer-executable program code for executing a differential operation; and a differential value at a predetermined point of an expression to be operated. A computer code that can be executed by a computer for determining whether or not the differential value can be calculated, and a computer for calculating the differential value by one-sided differential when it is determined that the differential value cannot be calculated by the two-sided differential. A storage medium storing a program code capable of being stored, and a program including: