Math Trigonometric functions asin() to get asin value of any radian as input in PHP

asin():

asin(X);

X is the angular value in radian. We get output as ARC SIN of the input angle. It is X==sin(asin(X))

It takes input range from +1 to -1 , for any other input it returns NAN ( not a number )

<?Php
echo asin(0); // Output is 0
echo "<br>";
echo asin(1); // Output  1.5707963267949
echo "<br>";
echo asin(-1); // Output is -1.5707963267949
echo "<br>";
echo asin(4); // Output is NAN 
?>

deg2rad() with asin()

We can use deg2rad() to convert Degree value to radian and then use asin().

<?Php
echo asin(deg2rad(0)); // 0
echo "<br>";
echo asin(deg2rad(1)); // 0.017454178737585
echo "<br>";
echo asin(deg2rad(-1)); // -0.017454178737585
?>

Plotting of SIN & SIN curves by using PHP GD function with deg2rad()

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