Inverse Functions
Maths: Edexcel A Level Pure Maths, topic 2.6.2
Inverse Functions
Inverse functions are the opposite of normal functions. They are written as f-1(x). Find the inverse of the function f(x) = 2x - 4:
Write the function
Replace f(x) with y
Swap x and y
Rearrange to find y in terms of x - step 1
Rearrange to find y in terms of x - step 2
Rearrange to find y in terms of x - step 3
Replace y with f-1(x)
Find f-1(2)
- You might also be asked to find the value of the inverse function for a certain value of x.
Test yourself on Inverse Functions
Inverse Functions
If f(x) = 6 + x, what is f-1(x)?
If f(x) = 1 + 1⁄2x, what is f-1(x)?