Inverse Function of a Quadratic Function, Choosing Between Plus or Minus ±, Example and Explanation

We learn how to find the inverse function of a quadratic function and how to choose between the plus or minus options we obtain in the process.

The method we learn here can be summarised in 3 steps:
- Step 1: swap x and y
- Step 2: rearrange to make y the subject
- Step 3: use the fact that the domain of a function is equal to the range of its inverse function to choose between plus or minus ±

******** TIMESTAMPS / CHAPTERS ********

00:00 Introduction
00:37 Domain of f(x), make a note of it
00:58 Step 1: swap x and y
01:42 Step 2 : make y the subject by completing the square (same as writing in vertex form)
04:41 Step 3 : use the fact that the domain of a function is equal to the range of its inverse function to choose between plus or minus ± and choose the inverse function
07:01: one-to-one mapping and horizontal line test full understanding