PHP sin() Function

The PHP sin() function returns trigonometric sine of an angle (angle should be in radians). In special cases it returns the following:

If the argument is NAN or an infinity, then the result is NAN.

In the graph below, sin(x) vs x is plotted.

Syntax

sin(number)

Parameters

number Required. Specify the angle in radian.

Return Value

Returns the trigonometric sine of an angle.

Example:

In the example below, sin() function is used to find out the trigonometric sine of an angle.

<?php
echo "sin(pi()/6) = ".sin(pi()/6)."\n";
echo "sin(pi()/4) = ".sin(pi()/4)."\n";
echo "sin(pi()/3) = ".sin(pi()/3)."\n"; 
echo "sin(deg2rad(45)) = ".sin(deg2rad(45))."\n";
echo "sin(M_PI/2) = ".sin(M_PI/2)."\n";
echo "sin(M_PI_4) = ".sin(M_PI_4)."\n";
echo "sin(NAN) = ".sin(NAN)."\n";
echo "sin(INF) = ".sin(INF)."\n";
?>

The output of the above code will be:

sin(pi()/6) = 0.5
sin(pi()/4) = 0.70710678118655
sin(pi()/3) = 0.86602540378444
sin(deg2rad(45)) = 0.70710678118655
sin(M_PI/2) = 1
sin(M_PI_4) = 0.70710678118655
sin(NAN) = NAN
sin(INF) = NAN

❮ PHP Math Reference