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title: Even and Odd Functions
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## Even and Odd Functions
### General Functions
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A function `f` is a mapping from a set A (input/domain) to a set B (output/co-domain).
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### Even Function:
A function `f(x)` is even if and only if `f(x) = f(-x)` .
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An example of an even function would be `f(x) = x^2` because `(-x)^2 = x^2` . For example, `f(2) = 2^2 = 4 = (-2)^2 = f(-2)` .
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The trigonometric functions - `cos(x)` and `sec(x)` are also even functions
### Odd Function
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A function `f(x)` is odd if and only if `f(x) = -f(-x)`
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An example of an odd function would be `f(x) = x^3` because `(-x)^3 = -x^3` , so `-(-x)^3 = x^3` . For example, `f(2) = 2^3 = 8 = -(-8) = -(-2)^3 = -f(-2)` .
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The trigonometric functions - `sin(x)` , `tan(x)` ,`cot(x)` and `cosec(x)` are also odd functions
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#### More Information:
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- [Wikipedia ](https://en.wikipedia.org/wiki/Even_and_odd_functions )