25 Numerics library [numerics]

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

25.8.5 Mathematical special functions [sf.cmath]

25.8.5.11 Incomplete elliptic integral of the first kind [sf.cmath.ellint_1]

double ellint_1(double k, double phi); float ellint_1f(float k, float phi); long double ellint_1l(long double k, long double phi);
Effects: These functions compute the incomplete elliptic integral of the first kind of their respective arguments k and phi (phi measured in radians).
Returns:
where k is k and φ is phi.