What is sin() in PHP?

The sin() function in PHP returns the sine of a number in radians.

The illustration below shows the mathematical representation of the sin() function.

Mathematical representation of the sine function

This sin() function only works for right-angle triangles.

Syntax

float sin(num)

Parameters

The sin() function requires a number that represents an angle in radians as a parameter.

To convert degrees to radians, use the following formula:

radians = degrees * ( M_PI / 180 )

Return value

sin() returns the sine of the number that is sent as a parameter. The return value is in the range [-1,1].

Code

<?php
#Positive number in radians
echo("sin(2.3): ");
echo (sin(2.3));
?>
<?php
#Negative number in radians
echo("sin(-2.3): ");
echo (sin(-2.3));
?>
<?php
#converting the degrees angle into radians and then applying sin()
#degrees = 90
echo("sin(90 * (M_PI / (180))): ");
echo (sin(90 * (M_PI / (180))));
?>
Attributions:
  1. undefined by undefined