H2 Maths 1.1 - Quadratic Inverse by Restricting Domain

What you will learn

• Goal: find the inverse of f(x) = 2 x^2 - 3 x - 1, which is not one-to-one over all reals.
• Restrict to the increasing branch x >= 3/4 (turning point from f'(x) = 0) so f becomes one-to-one.
• Complete the square: f(x) = 2 (x - 3/4)^2 - 17/8, so the range starts at -17/8.