asin

Definition and usage

asin() function returns the inverse sine of different values, and the result is a radian value between -PI/2 and PI/2.

Example

In this case, we will calculate the inverse sine of different values:

 <?php
echo ( asin ( 0.64 ) ) ;
echo ( asin ( 0 ) ) ;
echo ( asin ( - 1 ) ) ;
echo ( asin ( 1 ) ) ;
echo ( asin ( 2 ) )
?>

Try it yourself

grammar

 asin ( x )

illustrate

Returns the inverse sine value of x , in radians. asin() is the inverse function of sin() , which means that every value in the asin() range is a==sin(asin(a)) .

If the value of x is outside -1 to 1, return -1.#IND. If 1, the value of PI/2 is returned.