\[\operatorname{cel}\left(k_{c},p,a,b\right)=\int_{0}^{\pi/2}\frac{a{\cos}^{2}%
\theta+b{\sin}^{2}\theta}{{\cos}^{2}\theta+p{\sin}^{2}\theta}\frac{\,\mathrm{d%
}\theta}{\sqrt{{\cos}^{2}\theta+k_{c}^{2}{\sin}^{2}\theta}},\]