Find the inverse function of y = (e ^ X-1 / e ^ x) / 2?

Find the inverse function of y = (e ^ X-1 / e ^ x) / 2?

Let a = e ^ x
a-1/a=2y
a²-2ya-1=0
a=y±√(y²+1)
y0
So e ^ x = y + √ (Y & sup2; + 1)
So the inverse function is y = ln [x + √ (X & sup2; + 1)], X ∈ R