KleinInvariantJ

KleinInvariantJ[τ] gives the Klein invariant modular elliptic function J(τ).

Examples

Evaluate at a complex value:

KleinInvariantJ[I] // N
(* 1. *)

Plot the real part:

Plot3D[Re[KleinInvariantJ[x + I y]], {x, -1, 1}, {y, 0.5, 2}]

Please visit the official Wolfram Language Reference for more details.