EllipticE

EllipticE[m] gives the complete elliptic integral E(m).

EllipticE[ϕ, m] gives the elliptic integral of the second kind E(ϕ|m).

Examples

EllipticE[0.5]
(* 1.35064 *)

EllipticE[Pi/4, 0.5]
(* 0.748186 *)

Please visit the official Wolfram Language Reference for more details.