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LI. Mathematical Functions


These math functions will only handle values within the range of the integer and float types on your computer (this corresponds currently to the C types long resp. double). If you need to handle bigger numbers, take a look at the arbitrary precision math functions.

See also the manual page on arithmetic operators.


No external libraries are needed to build this extension.


There is no installation needed to use these functions; they are part of the PHP core.

Runtime Configuration

This extension has no configuration directives defined in php.ini.

Resource Types

This extension has no resource types defined.

Predefined Constants

The constants below are always available as part of the PHP core.

Table 1. Math constants

Constant Value Description
M_PI 3.14159265358979323846 Pi
M_E 2.7182818284590452354 e
M_LOG2E 1.4426950408889634074 log_2 e
M_LOG10E 0.43429448190325182765 log_10 e
M_LN2 0.69314718055994530942 log_e 2
M_LN10 2.30258509299404568402 log_e 10
M_PI_2 1.57079632679489661923 pi/2
M_PI_4 0.78539816339744830962 pi/4
M_1_PI 0.31830988618379067154 1/pi
M_2_PI 0.63661977236758134308 2/pi
M_SQRTPI 1.77245385090551602729 sqrt(pi) [4.0.2]
M_2_SQRTPI 1.12837916709551257390 2/sqrt(pi)
M_SQRT2 1.41421356237309504880 sqrt(2)
M_SQRT3 1.73205080756887729352 sqrt(3) [4.0.2]
M_SQRT1_2 0.70710678118654752440 1/sqrt(2)
M_LNPI 1.14472988584940017414 log_e(pi) [4.0.2]
M_EULER 0.57721566490153286061 Euler constant [4.0.2]
Only M_PI is available in PHP versions up to and including PHP 4.0.0. All other constants are available starting with PHP 4.0.0. Constants labeled [4.0.2] were added in PHP 4.0.2.

Table of Contents
abs?--?Absolute value
acos?--?Arc cosine
acosh?--?Inverse hyperbolic cosine
asin?--?Arc sine
asinh?--?Inverse hyperbolic sine
atan2?--?arc tangent of two variables
atan?--?Arc tangent
atanh?--?Inverse hyperbolic tangent
base_convert?--?Convert a number between arbitrary bases
bindec?--?Binary to decimal
ceil?--?Round fractions up
cosh?--?Hyperbolic cosine
decbin?--?Decimal to binary
dechex?--?Decimal to hexadecimal
decoct?--?Decimal to octal
deg2rad?--? Converts the number in degrees to the radian equivalent
exp?--?Calculates the exponent of e (the Neperian or Natural logarithm base)
expm1?--? Returns exp(number) - 1, computed in a way that is accurate even when the value of number is close to zero
floor?--?Round fractions down
fmod?--?Returns the floating point remainder (modulo) of the division of the arguments
getrandmax?--?Show largest possible random value
hexdec?--?Hexadecimal to decimal
hypot?--? Returns sqrt( num1*num1 + num2*num2)
lcg_value?--?Combined linear congruential generator
log10?--?Base-10 logarithm
log1p?--? Returns log(1 + number), computed in a way that accurate even when the val ue of number is close to zero
log?--?Natural logarithm
max?--?Find highest value
min?--?Find lowest value
mt_getrandmax?--?Show largest possible random value
mt_rand?--?Generate a better random value
mt_srand?--?Seed the better random number generator
octdec?--?Octal to decimal
pi?--?Get value of pi
pow?--?Exponential expression
rad2deg?--? Converts the radian number to the equivalent number in degrees
rand?--?Generate a random value
round?--?Rounds a float
sinh?--?Hyperbolic sine
sqrt?--?Square root
srand?--?Seed the random number generator
tanh?--?Hyperbolic tangent