# Proving these two angles are equal

I'm researching an abstract geometric property and I've discovered the problem depends on showing these two angles are equal for strictly positive x:

arctan(x) - arctan(x^3 +2x -((x^2 + 1)^(3/2)))

and

-arctan(x) + arctan(x^3 +2x + ((x^2 + 1)^(3/2)))

Any help would be greatly appreciated, I've been trying this for hours and I think I'm stuck in a rut.

Many Thanks!