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Functions

A function takes an element of one set and maps it to an element in another set.

Writing functions

Writing functions

  • We can write the function that doubles a number and then adds 3 in these ways.

Domain and Range

A function is a relation in which each possible input value leads to exactly one output value.

Domain

Domain

  • The input values make up the domain.
    • The domain of the function f(x) = x2 is all of the numbers from -∞ to +∞.
Range

Range

  • The output values make up the range.
    • The range of the function f(x) = x2 are all of the positive numbers and 0.
Allowed values

Allowed values

  • Certain functions are not defined for certain inputs.
    • f(x)=1xf(x)=\frac{1}{x} is not defined for x=0x=0 as f(0)=f(0) = \infty.
    • f(x)=xf(x) = \sqrt{x} is not defined for x<0x<0.
Jump to other topics
1

Numbers

2

Equations, Formulae & Identities

3

Sequences, Functions & Graphs

4

Geometry

5

Vectors & Transformation Geometry

6

Statistics & Probability

Practice questions on Functions

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