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PHP | sin( ) Function
• Last Updated : 08 Mar, 2018

Trigonometry is an important part of mathematics and PHP’s math functions provides us with some functions which are very useful for calculations involving trigonometry. The sin()function in PHP is used to find the sine value of a number.
The sine() function returns a float value between -1 and 1, which represents the sine of the angle passed to it as argument. The argument parameter must be in radians.

Syntax:

`float sin(\$value)`

Parameters: This function accepts a single parameter value. It is the number whose sine value you want to find. The value of this parameter must be in radians.

Return Value: It returns a floating point number which is the sine value of number passed to it as argument.

Examples:

```Input : sin(3)
Output : 0.14112000805987

Input : sin(-3)
Output : -0.14112000805987

Input : sin(2*M_PI)
Output : 1

Input : sin(0)
Output : 0
```

Below programs illustrate sin() function in PHP:

• Passing 3 as a parameter:
 `      `

Output:

`0.14112000805987`
• Passing -3 as a parameter:
 `      `

Output:

`-0.14112000805987`
• When (2*M_PI) is passed as a parameter, M_PI is a constant in PHP whose value is 3.1415926535898:
 ```      `

Output:

`1`
• Passing 0 as a parameter:
 `      `

Output:

`0`

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