It  seed the better random number generator

Example

<?php
mt_srand(mktime());
echo(mt_rand());
?>

Output

254590754

It generates a better random value

Example

<?php
echo mt_rand(111,2222);
?>

Output

1787

It returns  largest possible random value

Example

<?php
echo mt_getrandmax();
?>

Output

2147483647

It returns lowest value

Example

<?php
echo min(10,11,17)
?>

Output

10

It returns maximum value

Example

<?php
echo max(10,11,17)
?>

Output

17

It returns natural logarithm

Example

<?php
echo log(17)
?>

Output

2.8332133440562

It returns log(1+x)

Example

<?php
echo log1p(1)
?>

Output

0.69314718055995

It returns  Base-10 logarithm value

<?php
echo log10(1);
?>

Output

0

It returns  combined linear congruential generator

Example

<?php
echo lcg_value();
?>

Output

0.91341065078248

It checks whether a value is not a number

Example

<?php
echo is_nan(acos(2.01));
?>

Output

1