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LI. Mathematical Functions

Introduction

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.

Math constants

The following values are defined as constants in PHP by the math extension:

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
atan -- Arc tangent
atanh -- Inverse hyperbolic tangent
atan2 -- arc tangent of two variables
base_convert -- Convert a number between arbitrary bases
bindec -- Binary to decimal
ceil -- Round fractions up
cos -- Cosine
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 -- e to the power of ...
expm1 -- Returns exp(number) - 1, computed in a way that accurate even when the value of number is close to zero
floor -- Round fractions down
getrandmax -- Show largest possible random value
hexdec -- Hexadecimal to decimal
hypot -- Returns sqrt( num1*num1 + num2*num2)
lcg_value -- Combined linear congruential generator
log -- Natural logarithm
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
max -- Find highest value
min -- Find lowest value
mt_rand -- Generate a better random value
mt_srand -- Seed the better random number generator
mt_getrandmax -- Show largest possible random value
number_format -- Format a number with grouped thousands
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
sin -- Sine
sinh -- Hyperbolic sine
sqrt -- Square root
srand -- Seed the random number generator
tan -- Tangent
tanh -- Hyperbolic tangent

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