asin

(PHP 4, PHP 5, PHP 7, PHP 8)

asin — Arc sine

Description

asin(float $num): float

Returns the arc sine of num in radians. asin() is the inverse function of sin(), which means that $num == sin(asin($num)) for every value of num that is in the domain of asin().

Parameters

num: The argument to process

Return Values

The arc sine of num in radians

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User Contributed Notes 1 note

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rahmatjon at gmail dot com ¶

3 years ago

Hello!
Please put this example below the asin() function's description.
Thank you!

Example:
<?php
    $arg = 0.5;
    $val = asin($arg);
    echo "asin(" . $arg . ") = " . $val . " radians.<br/>";
    echo "Pi value = " . pi() . "<br/>";   
    echo "asin(" . $arg . ") = " . $val/pi()*180 . " degrees<br/>";

    $arg = 1;
    $val = asin($arg);
    echo "asin(" . $arg . ") = " . $val . " radians.<br/>";
    echo "Pi value = " . pi() . "<br/>";   
    echo "asin(" . $arg . ") = " . $val/pi()*180 . " degrees<br/>";
?>