The math help thread

Need help on my math assignment due friday morning.

I don't get why they throw in a trig identity question in the assignment when we're not even learning it...

prove:
arcsin ((x-1)/(x+1))=2arctan(sqrt(x))-(pi/2)

I haven't quite gotten there, but this is what I've managed...

Code:

Reference:
Hypotenuse = x + 1
Opposite = x - 1
Adjacent = 2*sqrt(x)
ᴨ = PI

arcsin((x - 1) / (x + 1)) = 2*arctan(sqrt(x)) - (ᴨ / 2)
1/2*arcsin((x - 1) / (x + 1)) = arctan(sqrt(x)) - (ᴨ / 4)
tan(1/2 * arcsin((x - 1) / (x + 1))) = sqrt(x) - 1
(x - 1) / (4*sqrt(x)) = sqrt(x) - 1

Seems to me that trying to do this problem without trigonometric identities or formulas isn't possible, given the nature of tangent.

Okay I've gotten closer: x = sqrt(x)*sqrt(x + 1). Sorry, seems like I can't help after all =(