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pow

(PHP 3, PHP 4, PHP 5)

pow -- Exponential expression

Description

number pow ( number base, number exp )

Returns base raised to the power of exp.

Warning

In PHP 4.0.6 and earlier pow() always returned a float, and did not issue warnings.

Parameters

base

The base to use

exp

The exponent

Return Values

base raised to the power of exp. If the result can be represented as integer it will be returned as type integer, else it will be returned as type float. If the power cannot be computed FALSE will be returned instead.

ChangeLog

VersionDescription
Since 4.0.6 The function will now return integer results if possible, before this it always returned a float result. For older versions, you may receive a bogus result for complex numbers.
Since 4.2.0 PHP stops to emit a warning if the value can't be computed, it will now silently return FALSE only.

Examples

Example 1. Some examples of pow()

<?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
?>

See Also

exp()
sqrt()
bcpow()
gmp_pow()

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