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title: Even and Odd Functions
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## Even and Odd Functions

### General Functions

A function `f` is a mapping from a set A (input/domain) to an set B (output/co-domain). It can be of different types on the basis of a number of classifications.

### Even Function:

A function `f(x)` is even if and only if `f(x) = f(-x)`.

An example of an even function would be `f(x) = x^2` because `f(2) = 2^2 = 4 = (-2)^2 = f(-2)`.

The trigonometric functions -  `cos(x)` and `sec(x)` are also even functions

### Odd Function

A function `f(x)` is even if and only if `f(x) = -f(-x)`

An example of an odd function would be `f(x) = x^3` because `f(2) = 2^3 = 8 = -(-8) = -(-2)^3 = -f(-2)`.

The trigonometric functions -  `sin(x)`, `tan(x)`,`cot(x)` and `cosec(x)` are also even functions

#### More Information:
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- [Wikipedia](https://en.wikipedia.org/wiki/Even_and_odd_functions)