2.3.7

Inverse Functions

Test yourself

Inverse Functions

Inverse functions complete a function in reverse, i.e. working backwards. You need to know how to work with them and work them out.

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Inverse functions

  • You need to know how to find the inverse of a function.
    • You can do this by changing the subject of the equation.
    • f−1(x) is the inverse of f(x).
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Example

  • If f(x) = 2x − 4, what is the inverse of f(x)?
    • Step 1 is to make y = f(x).
    • y = 2x − 4
  • You then need to swap x and y in the equation.
    • x = 2y − 4
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Finally, replace y with f-1(x)

  • This is the inverse of f(x)

Jump to other topics

1Number

1.1Using Numbers

1.2Fractions, Decimals & Percentages

1.3Powers & Roots

1.4Accuracy

2Algebra

2.1Introduction to Algebra

2.2Manipulating Algebra

2.3Proofs & Functions

2.4Straight Line Graphs

2.5Common Graphs

2.6Transformations & Tangents

2.7Properties of Graphs

2.8Solving Equations

2.9Inequalities

2.10Sequences

3Ratio

4Geometry

4.1Introduction to Geometry

4.2Triangles & Quadrilaterals

4.3Transformations

4.4Circle Basics

4.5Circle Theorems

4.6Measurements & Units

4.7Calculating Area

4.8Triangle Formulae

4.93D Shapes

4.10Vectors

5Probability

6Statistics

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