f-x-x-3-2x-Find-f-1-x-

Question Number 93350 by abony1303 last updated on 12/May/20

f (x) = x^{3} + 2 x

F i n d : f^{- 1} (x)

Answered by Rio Michael last updated on 12/May/20

f (x) = x^{3} + 2 x

let y = f (x) \Rightarrow y = x^{3} + 2 x or x = y^{3} + 2 y

\Rightarrow y = \sqrt[3]{\frac{9 x + \sqrt{81 x^{2} + 96}}{18}} + \sqrt[3]{\frac{9 x - \sqrt{81 x^{2} + 96}}{18}} = f^{- 1} (x)

by {cardano}^{'} s method