Question

if f(x)= x^5 + x^3 + x find f^-1(3) and f(f^-1(2))

really confused because i thought inverse meant switch x and y then isolate y, except i can't do that here??

Answer 1

let f^-1 (3) = X
so f(X) = 3
got this ?

Answer 2

so plug in f(x) = 3
so,
x+x^3+x^5 = 3

which value of x can you guess to be solution/root of this equation?

Answer 3

also, f( f^-1 (x)) = x
so, f(f^-1(2)) = ... ?
quite easy to figure out

Answer 4

okay so first part is 1

Answer 5

and second part is 2

Answer 6

yup! :)

Answer 7

any doubts ?