Let fx x3 2x 3 Find f13SolutionGiven f x x3 2x 3 Let y

Solution

Given f (x) = x³ + 2x + 3

Let y = f (x) => x = f^-1 (y), i.e. for y = 3; x = f^-1 (3)

Hence, 3 = x³ + 2x + 3, or, x³ + 2x = 0

Therefore, x (x² + 2) = 0, i.e. x = 0, x = + i_/2, and - i_/2

  f^-1 (3) = {0, + i_/2, - i_/2}, where, i = _/(-1).