Exponential and Logarithmic Functions in PHP
exp() — Calculates the exponent of e
expm1() — Returns exp(number) – 1, computed in a way that is accurate even when the value of number is close to zero
log10() — Base10 logarithm
log1p() — Returns log(1 + number), computed in a way that is accurate even when the value of number is close to zero
log() — Natural logarithm
pow() — Exponential expression
sqrt() — Square root
PHP exp()
Function
What does exp()
do?
The PHP
function will give you exp()
e
raised to the power of arg
.
PHP exp()
Syntax
exp ( float $arg ) : float
PHP exp()
Parameters

arg
— The argument to process
PHP exp()
Return Value
The PHP exp()
function returns ‘e’ raised to the power of arg
PHP exp()
Working Examples
1. exp() example
<?php
echo exp(12) . "\n";
echo exp(5.7);
?>
Output of the above code:
1.6275E+005
298.87
Important Points about PHP exp()
Function

‘
e
‘ is the base of the natural system of logarithms, or approximately 2.718282.
PHP expm1()
Function
What does expm1()
do?
The PHP
function will give you exp(number) – 1, computed in a way that is accurate even when the value of number is close to zero .expm1()
PHP expm1()
Syntax
expm1 ( float $arg ) : float
PHP expm1()
Parameters

arg
— The argument to process
PHP expm1()
Return Value
The PHP expm1()
function returns ‘e’ to the power of arg
minus one
Changelog for PHP expm1() Function
5.3.0 — This function is now available on all platforms
PHP log()
Function
What does log()
do?
The PHP
function will give you logbase log()
arg
, otherwise log()
return the natural logarithm of arg
.
PHP log()
Syntax
log ( float $arg [, float $base = M_E ] ) : float
PHP log()
Parameters

arg
— The value to calculate the logarithm for 
base
— The optional logarithmic base to use (defaults to ‘e’ and so to the natural logarithm).
PHP log()
Return Value
The PHP log()
function returns the logarithm of arg
to base
, if given, or the natural logarithm.
PHP log10()
Function
What does log10()
do?
The PHP
function will give you the base10 logarithm of log10()
arg
.
PHP log10()
Syntax
log10 ( float $arg ) : float
PHP log10()
Parameters

arg
— The argument to process
PHP log10()
Return Value
The PHP log10()
function returns the base10 logarithm of arg
PHP log1p()
Function
What does log1p()
do?
The PHP
function will give you log(1 + number), computed in a way that is accurate even when the value of number is close to zero .log1p()
PHP log1p()
Syntax
log1p ( float $number ) : float
PHP log1p()
Parameters

number
— The argument to process
PHP log1p()
Return Value
The PHP log1p()
function returns log(1 + number
)
Changelog for PHP log1p() Function
5.3.0 — This function is now available on all platforms
PHP pow()
Function
What does pow()
do?
The PHP
function will give you pow()
base
raised to the power of exp
.
PHP pow()
Syntax
pow ( number $base , number $exp ) : number
PHP pow()
Parameters

base
— The base to use 
exp
— The exponent
PHP pow()
Return Value
The PHP pow()
function returns d with integer type, otherwise it will be returned as a float.
PHP pow()
Working Examples
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(10, 1); // 0.1
echo pow(1, 5.5); // PHP >=5.2.2: NAN
echo pow(1, 5.5); // PHP <5.2.2: NAN
?>
Important Points about PHP pow()
Function

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

This function will convert all input to a number, even nonscalar values, which could lead to weird results.
Additional Tips from Fellow Developers
Contributed By: chris
Many notations use "^" as a power operator, but in PHP (and other Cbased languages) that is actually the XOR operator. You need to use this 'pow' function, there is no power operator.
i.e. 3^2 means "3 XOR 2" not "3 squared".
It is particular confusing as when doing Pythagoras theorem in a 'closet points' algorithm using "^" you get results that look vaguely correct but with an error.
Contributed By: gilthans
Note that pow(0, 0) equals to 1 although mathematically this is undefined.
PHP sqrt()
Function
What does sqrt()
do?
The PHP
function will give you the square root of sqrt()
arg
.
PHP sqrt()
Syntax
sqrt ( float $arg ) : float
PHP sqrt()
Parameters

arg
— The argument to process
PHP sqrt()
Return Value
The PHP sqrt()
function returns the square root of arg
or the special value NAN for negative numbers.
PHP sqrt()
Working Examples
1. sqrt() example
<?php
// Precision depends on your precision directive
echo sqrt(9); // 3
echo sqrt(10); // 3.16227766 ...
?>
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Author: Nitish Kumar
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