29 Numerics library [numerics]

29.9 Mathematical functions for floating-point types [c.math]

29.9.5 Mathematical special functions [sf.cmath]

29.9.5.4 Complete elliptic integral of the first kind [sf.cmath.comp_ellint_1]

double comp_ellint_1(double k); float comp_ellint_1f(float k); long double comp_ellint_1l(long double k);

Effects: These functions compute the complete elliptic integral of the first kind of their respective arguments k.

Returns:

where k is k.