/ ____\ | / x | atan\\/ E /
atan(sqrt(E^x))
x - 2 e ---------- / x\ 2*\1 + E /
x / x \ - | 2*e | 2 |1 - ------|*e | x| \ 1 + e / --------------- / x\ 4*\1 + e /
x / 2*x x \ - |1 e e | 2 |- + --------- - ------|*e |8 2 x| | / x\ 1 + e | \ \1 + e / / --------------------------- x 1 + e