What is an inverse function?

• An inverse function does the exact opposite of the function it came from
• Eg. if the function “doubles the number and adds 1”then its inverse will “subtract 1 and halve the result”
• It is the?INVERSE?operations in the?reverse?order

What do inverse functions look like?

• An inverse function f-1 can be written as:f^-1(x) = … or f^-1?: x ? …
• Eg. if f(x) = 2x + 1 its inverse can be written as:f^-1(x) = x – 1 / 2? ?or? ?f^-1: x ? x – 1 / 2

What do you find an inverse function?

1. Write the function in the form y=…
2. SWAP the xs and ys to get x=…
3. REARRANGE to give y=… again
4. Write as f^-1(x) = … (or f^-1?: x ? …)

• Eg. if f(x)=2x+1 its inverse can be found as follows …y= 2x + 1 1? ?–? ?1. Write the function as y=…x = 2y + 1 2? –? ?2. Swap the xs and ysx – 1= 2y 3? ?–? ?3. Rearrange into the form y=… (or …=y)

  x – 1 / 2 = yf^-1(x) = x – 1 / 2? – 4. Write as f^-1(x)=…