Question

Which of the following functions are inverse functions of each other?
1. f(x)=sinx and g(x) = cosx
2. f(x) = 3+8x and g(x) 3-8x
3. f(x) = e^x and g(x) = lnx
4. f(x) = 2x-4 and g(x) = (-1/2)x +4

Answer 1

and why.

Answer 2

3. f(x)=e^x and g(x)=ln x

Just interchange x and y.