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 Last updated: Fri, 17 May 2013

# Mathematical Functions

• Introduction
• Installing/Configuring
• Predefined Constants
• Math Functions
• 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
• 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 — Calculates the exponent of e
• 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 — Calculate the length of the hypotenuse of a right-angle triangle
• is_finite — Finds whether a value is a legal finite number
• is_infinite — Finds whether a value is infinite
• is_nan — Finds whether a value is not a number
• lcg_value — Combined linear congruential generator
• log10 — Base-10 logarithm
• log1p — Returns log(1 + number), computed in a way that is accurate even when the value 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 integer
• round — Rounds a float
• sin — Sine
• sinh — Hyperbolic sine
• sqrt — Square root
• srand — Seed the random number generator
• tan — Tangent
• tanh — Hyperbolic tangent

 Last updated: Fri, 17 May 2013

User Contributed Notes Math - [3 notes]
-1
Hayley Watson
3 months ago
``` Provides a function to rescale numbers so that the range [a,b] fits into the range [c,d]. <?php function rescale(\$ab, \$cd) {     list(\$a, \$b) = \$ab;     list(\$c, \$d) = \$cd;     if(\$a == \$b)     {         trigger_error("Invalid scale", E_USER_WARNING);         return false;     }     \$o = (\$b * \$c - \$a * \$d) / (\$b - \$a);     \$s = (\$d - \$c) / (\$b - \$a);     return function(\$x)use(\$o, \$s)     {         return \$s * \$x + \$o;     }; } \$fahr2celsius = rescale([32, 212], [0, 100]); echo  \$fahr2celsius(98.6); // 37°C ?> ```
-3
Sanjay Ichalkaranje
4 years ago
``` This is the only function I searched that I did not find anywhere on the Internet. This function calculates standard normal cumulative distribution for a particular value. This is NORMSDIST(x) in MS-Excel or OpenOffice.org Calc program. <? function normalDist(\$zScore) {     \$p = floatval(0.2316419);     \$b1 = floatval(0.319381530);     \$b2 = floatval(-0.356563782);     \$b3 = floatval(1.781477937);     \$b4 = floatval(-1.821255978);     \$b5 = floatval(1.330274429);     \$t = 1/(1 + (\$p * floatval(\$zScore)));     \$zx = (1/(sqrt(2 * pi())) * (exp(0 - pow(\$zScore, 2)/2)));     \$px = 1 - floatval(\$zx) * ((\$b1 * \$t) + (\$b2 * pow(\$t, 2)) + (\$b3 * pow(\$t, 3)) + (\$b4 * pow(\$t, 4)) + (\$b5 * pow(\$t,5)));     return \$px; } ?> ```
-4
Anonymous:
4 years ago
``` Here is a simple number digit counter function, I used it to check if a number is a palindrome or not, Plus a Distance function, slope formula, sum from one to an integer, sum of odd numbers from one to specified number, and last but not least the sum of the squares of the values of the sine of x, and the cosine of y. <?php function digit_count(\$num){ for(\$i=0;pow(10,\$i)<=\$num;\$i++){   if(pow(10,\$i+1)>\$num){          \$num_digits = \$i+1;              } } return \$num_digits; } function distance(\$x_1,\$y_1,\$x_2,\$y_2){ return sqrt(pow(\$x_1-\$x_2,2)+pow(\$y_1-\$y_2,2)); }     function slope(\$x_1,\$y_1,\$x_2,\$y_2){ return (\$y_2-\$y_1)/(\$x_2-\$x_1); } // example sum(20)=210=1+2+3+...+20 function sum(\$x){ return (\$x)(\$x+1)/2; } // example odd(15)=225=1+3+5+7+9+...+15 function odd(\$x){ if((\$x%2) == 0){ \$x-=1; } \$y=(\$x+1)/2; return pow(\$y,2); //Same as \$y*\$y; } function (\$x,\$y){ if(\$x=90-\$y){ echo "(Sine of \$x)^2 + (Cosine of \$y)^2=1"; \$value = 1; }else{ \$value = pow(sin(\$x),2)+pow(cos(\$y),2); } return \$value; } ?> ```