Composite & Inverse
Maths: Edexcel IGCSE Higher, topic 3.2.2
Composite Functions
If f(x) = x2 - 1 and g(x) = x + 3, then what is fg(2)?
Write functions
Combine
Sub in x = 2
fg(2) = 24
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)
Test yourself on Composite & Inverse
Composite Functions
Composite Functions
Inverse Functions
If f(x) = 6 + x, what is f-1(x)?
If f(x) = 1 + 1⁄2x, what is f-1(x)?