php man page for pow

POW(3)									 1								    POW(3)

pow - Exponential expression

SYNOPSIS
       number pow (number  $base, number  $exp)

DESCRIPTION
	Returns $base raised to the power of $exp.

       Note

	       In PHP 5.6 onwards, you may prefer to use the ** operator.

PARAMETERS
	      o $base
		- The base to use

	      o $exp
		- The exponent

RETURN VALUES
       $base  raised to the power of $exp. If both arguments are non-negative integers and the result can be represented as an integer, the result
       will be returned with integer type, otherwise it will be returned as a float.

EXAMPLES
       Example #1

	      Some examples of pow(3)

	      <?php

	      var_dump(pow(2, 8)); // int(256)
	      echo pow(-1, 20); // 1
	      echo pow(0, 0); // 1

	      echo pow(-1, 5.5); // PHP >4.0.6	NAN
	      echo pow(-1, 5.5); // PHP <=4.0.6 1.#IND
	      ?>

NOTES
       Note

	       This function will convert all input to a number, even non-scalar values, which could lead to weird results.

SEE ALSO
       exp(3), sqrt(3), bcpow(3), gmp_pow(3).

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