Dear Friends,
Some complete elliptic integral of first and second kind E(k) and K(k) can be evaluated for some particular values of "k" in terms of Euler Gamma function. For example, for k = sqrt(2)/2, E(k) and K(k) can be evaluated in terms of Gamma(1/4). Regarding this topic, I raise the following two questions:
1 - I am curious, about the mathematical procedure which is implemented to transform the elliptic integral to an integral solvable using Gamma function. I was able to figure out the transformation for the case k = sqrt(2)/2. But couldn't do it for other values of "k" for which I know that their corresponding elliptic integrals are indeed expressed in terms of Gamma function (e.g. k = (sqrt(6) - sqrt(2)/4). What is the general form of the transformation applied to the elliptic integral to generate the resulting integral solvable in terms of Gamma function?
2 - Is there a mathematical formula through which we can tell the values of "k" whose corresponding elliptic integrals K(k) and E(k) are solvable by Euler Gamma function? and if so, is there a direct solution to the integral in terms of "k"?
Please support your answers with necessary references whenever possible.
Thanks in advance for your help.