I want to simplify with Mathematica 11 the following algebraic expression under the assumptions $x<0$ and $y>0$:
A= (-x + Sqrt[x^2 + y])/Sqrt[2 x^2 + y - 2 x Sqrt[x^2 + y]]
A short calculation yields
A = 1. But Mathematica seems not able to obtain that result when the following expression is evaluated:
Is it possible to help Mathematica to solve this?
Thanks for your answer.