Find (f o g)(t) and simplify... anyone?

Question

f(x)= x / sqr(1-x^2)
g(x)= g(t) = sin(t) for 0 < t < (Pi/2)

Find (f o g)(t) and simplify...

got the answer, THANKS, but can anyone explain me why the answer is tan(t)?

Answer 1

tan(t)

yes i can

fog(t) = f(sin(t)) = sin(t) / sqrt(1-sin^2(t))

1-sin^2(t) = cos^2(t)

thus

sin(t) / sqrt(1-sin^2(t)) = sin(t) / cos(t) = tan (t)