pi() returns an approximation of pi. The returned float has a precision based on the precision directive in php.ini, which defaults to 14. Also, you can use the M_PI constant which yields identical results to pi().

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log() - Natural logarithm

If the optional base parameter is specified, log() returns logbase arg, otherwise log() returns the natural logarithm of arg.

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As always you can calculate the logarithm in base b of a number n, but using the mathematical identity: logb(n) = log(n)/log(b), where log is the neperian (or natural) logarithm.

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The log()
The log() function returns the natural logarithm (base E) of a number.

Syntax
log(x,base)
Example
In the following example we will use the log() function on different numbers:

<?php
echo(log(2.7183) . "<br />");
echo(log(2) . "<br />");
echo(log(1) . "<br />");
echo(log(0) . "<br />");
echo(log(-1))
?>

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For arbitrary precision mathematics PHP offers the Binary Calculator which supports numbers of any size and precision, represented as strings.

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These functions are only available if PHP was configured with --enable-bcmath. In PHP 3, these functions are only available if PHP was not configured with --disable-bcmath.

The windows version of PHP has built in support for this extension. You do not need to load any additional extension in order to use these functions.

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bcadd() adds the left_operand to the right_operand and returns the sum in a string. The optional scale parameter is used to set the number of digits after the decimal place in the result.

For example:

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<?php
echo decoct("30") . "<br />";
echo decoct("10") . "<br />";
echo decoct("1587") . "<br />";
echo decoct("70");
?>

It convert decimal number into octal number

output is
36
12
3063
106

<?php
echo octdec("36") . "<br />";
echo octdec("12") . "<br />";
echo octdec("3063") . "<br />";
echo octdec("106");
?>
It converts an octal number to a decimal number
output
30
10
1587
70

<?php
echo dechex("30") . "<br />";
echo dechex("10") . "<br />";
echo dechex("1587") . "<br />";
echo dechex("70");
?>

IT convert decimal number into hexadecimal number
output
1e
a
633
46

bccomp() compares the left_operand to the right_operand and returns the result as an integer. The optional scale parameter is used to set the number of digits after the decimal place which will be used in the comparison. The return value is 0 if the two operands are equal. If the left_operand is larger than the right_operand the return value is +1 and if the left_operand is less than the right_operand the return value is -1.

For e.g

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bcdiv() divides the left_operand by the right_operand and returns the result. The optional scale sets the number of digits after the decimal place in the result, which defaults to 0.

For e.g

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bcmul() Multiply two arbitrary precision number and Multiply the left_operand by the right_operand and returns the result. The optional scale sets the number of digits after the decimal place in the result.

For e.g

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Hi

log10()
The log10() function returns the base-10 logarithm of a number.
for example
OutPut for this example
Regards
Falcon

hypot()
The hypot() function returns the length of the hypotenuse of a right-angle triangle.

Syntax
hypot(x,y)

Example
<?php
echo hypot(2,3) . "<br />";
echo hypot(3,6) . "<br />";
echo hypot(3,6) . "<br />";
echo hypot(1,3);
?>

The output of the code above will be:

3.60555127546
6.7082039325
6.7082039325
3.16227766017

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mt_rand()
The mt_rand() function returns a random integer using the Mersenne Twister algorithm.

If this function is called without parameters, it returns a pseudo-random value between 0 and RAND_MAX.

If you want a random number between 10 and 100 (inclusive), use mt_rand (10,100).

Syntax
mt_rand(min,max)

Example
In this example we will return some random numbers:

<?php
echo(mt_rand() . "<br />");
echo(mt_rand() . "<br />");
echo(mt_rand(10,100))
?>

The output of the code above could be:

1150905288
613289478
21

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bcmod() Get modulus of an arbitrary precision number

For e.g

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bcpow() Raise an arbitrary precision number to another

Raise x to the power y

For e.g

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expm1()
The expm1() function returns the value of Ex-1, where E is Euler's constant (approximately 2.7183) and x is the number passed to it.

Syntax

expm1(x)

Parameter Description
x Required. A number

Example

In the following example we will use the expm1() function on different numbers:

<?php
echo(expm1(1) . "<br />");
echo(expm1(-1) . "<br />");
echo(expm1(5) . "<br />");
echo(expm1(10))
?>

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bcpowmod() Raise an arbitrary precision number to another, reduced by a specified modulus

Use the fast-exponentiation method to raise x to the power y with respect to the modulus modulus. The optional scale can be used to set the number of digits after the decimal place in the result.

Because this method uses the modulus operation, non-natural numbers may give unexpected results. A natural number is any positive non-zero integer.

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