PHP cos


PHP cos(x) function returns the cosine value of x. The principle values for x is [-∞,∞].

<?PHP
	echo cos(M_PI); //-1
	echo cos(M_PI/3); //0.5
?>

deg2rad() function can be used to convert degree to radian angle.
<?PHP
	echo cos(deg2rad(60));  //0.5
	echo cos(deg2rad(30));  //0.86602540378444
?>

Cosine y=cos(x) Graph
X
(deg)
X
(Rad)
Y=cosine(X)
180 ̊ π -1
150 ̊ 5π/6 -0.866025
135 ̊ 3π/4 -0.707107
120 ̊ 2π/3 -0.5
90 ̊ π/2 0
60 ̊ π/3 0.5
45 ̊ π/4 0.707107
30 ̊ π/6 0.866025
0 ̊ 0 1