Definition and Usage
Most trigonometric functions like sin, cos, tan etc require angle argument in radians. Whereas, in practice angle is represented in degrees. The rad2deg() function proves useful in conversion of radian angle to degrees.
This function returns a float number such that number=rad2deg(x) where x is angle in radians. angle in radian = angle in deg *180/pi
For example rad2deg(Π) is equal to 180 degrees
Syntax
rad2deg ( float $number ) : float
Parameters
| Sr.No | Parameter & Description |
|---|---|
| 1 | number A float number reprsenting angle in radians |
Return Values
PHP rad2deg() function returns a float number that represents angle in degrees.
PHP Version
This function is available in PHP versions 4.x, PHP 5.x as well as PHP 7.x.
Example
Following example calculates radian equivalent of Π radians −
<?php $angle=M_PI; echo "angle in degrees = " . rad2deg($angle); ?>
Output
This will produce following result −
rad2deg(3.1415926535898) = 180
Example
PHP constant M_PI_4 is equal to 45 degrees. We can confirm the result by following example. −
<?php
$angle=M_PI_4;
echo "rad2deg(" . $angle . ") = " . rad2deg($angle);
?>Output
This will produce following result −
rad2deg(0.78539816339745) = 45
Example
Non numeric argument produces error: −
<?php
$angle="Hello";
echo "rad2deg(" . $angle . ") = " . rad2deg($angle);
?>Output
This will produce following result −
PHP Warning: rad2deg() expects parameter 1 to be float, string given
Example
The argument number can be a binary, octal or hexadecimal decimal number. Following example converts ox0110 angle (in radians) to degrees
<?php
$angle=0b0110;
echo "rad2deg(" . $angle . ") = " . rad2deg($angle);
?>Output
This will produce following result −
rad2deg(6) = 343.77467707849