for f(x) = x^3 + 1, (f o f^-1) (269)= ?

Question

Find the inverse of the function

Answer 1

(f o f^-1)(x) = x, so (f o f^-1)(269) = 269

Long way: y=x³+1 Find inverse: x=y³+1, x - 1 = y³, cuberroot(x-1) = y = f^-1(x)

f o f^-1 = [ cuberroot(x-1) ]³ + 1 = x-1 + 1 = x