Math Functions in PHP: Part 5

Introduction

The PHP math functions handle values within the range of integer and float types. In this article I describe some of the PHP math functions. To learn about some other MATH functions, go to PART 1 , PART 2 and PART 3.

PHP log() function

The PHP math log function is used to return the natural logarithm (base E) of a number.

Syntax

log( number, base)

Parameters in log function

It takes two parameters; they are:
 

Parameter	Description
number	It specifies a number.
base	The optional logarithmic base to use (defaults to "e" and so to the natural logarithm).

Example of log function

<?php

$val1=log(2);

$val2=log(0);

$val3=log(1.232);

$val4=log(1);

echo "log value of <b>2</b> is <b>$val1</b> <br />";

echo "log value of <b>0</b> is <b>$val2</b> <br />";

echo "log value of <b>1.232</b> is <b>$val3</b> <br />";

echo "log value of <b>1</b> is <b>$val4</b> <br />";

?>

Note: The code above is used to convert numbers to the natural logarithm (base E) of a number. So in the above example the numbers "2", "0", "1.232" and "1" are converted to the natural logarithm of the number.

Output


 

PHP log10() function

The PHP math log function is used to return the base-10 logarithm of a number.

Syntax

log10( number)

Parameters in log10 function

It takes one parameter; it is:
 

Parameter	Description
number	It specifies a number.

Example of log10 function

<?php

$val1=log10(2);

$val2=log10(0);

$val3=log10(1.232);

$val4=log10(1);

echo "log10 value of <b>2</b> is <b>$val1</b> <br />";

echo "log10 value of <b>0</b> is <b>$val2</b> <br />";

echo "log10 value of <b>1.232</b> is <b>$val3</b> <br />";

echo "log10 value of <b>1</b> is <b>$val4</b> <br />";

?>

Note: The above code is used to convert numbers to the base-10 logarithm of a number. So in the above example the numbers "2", "0", "1.232" and "1" are converted to the base-10 logarithm of the number.

Output

PHP log1p() function

The PHP math log function is used to return the log(1+a) , where a is a number, computed in a way that is accurate even when the value of a is close to zero.

Syntax

log1p( number)

Parameters in log10 function

It takes one parameter; it is:
 

Parameter	Description
number	It specifies a number.

Example of log1p function

<?php

$val1=log1p(2);

$val2=log1p(0);

$val3=log1p(1.232);

$val4=log1p(1);

echo "log1p value of <b>2</b> is <b>$val1</b> <br />";

echo "log1p value of <b>0</b> is <b>$val2</b> <br />";

echo "log1p value of <b>1.232</b> is <b>$val3</b> <br />";

echo "log1p value of <b>1</b> is <b>$val4</b> <br />";

?>

Note: The above code is used to convert numbers to the log(1+a). So in the above example the numbers "2", "0", "1.232" and "1" are converted to log(1+a).

Output