#Math Functions

The math: namespace provides mathematical functions beyond basic arithmetic. These map directly to System.Math in .NET.

All functions are in the math: namespace: xmlns:math="http://www.w3.org/2005/xpath-functions/math".

#Constants

#math:pi()

Returns the value of π.

math:pi()   => 3.141592653589793

C# equivalent: Math.PI

#math:e()

Returns Euler's number. New in XPath 4.0.

math:e()   => 2.718281828459045

C# equivalent: Math.E

#Exponential and Logarithmic

#math:exp()

Returns e raised to the given power.

math:exp(1)    => 2.718281828459045  (: e^1 :)
math:exp(0)    => 1.0
math:exp(2)    => 7.38905609893065

C# equivalent: Math.Exp(1)

#math:exp10()

Returns 10 raised to the given power.

math:exp10(2)   => 100
math:exp10(3)   => 1000
math:exp10(0)   => 1

C# equivalent: Math.Pow(10, 2)

#math:log()

Returns the natural logarithm (base e).

math:log(1)                => 0
math:log(math:e())         => 1
math:log(10)               => 2.302585...

C# equivalent: Math.Log(10)

#math:log10()

Returns the base-10 logarithm.

math:log10(100)    => 2
math:log10(1000)   => 3
math:log10(1)      => 0

C# equivalent: Math.Log10(100)

#math:pow()

Raises a number to a power.

math:pow(2, 10)    => 1024
math:pow(3, 0)     => 1
math:pow(25, 0.5)  => 5  (: square root :)

C# equivalent: Math.Pow(2, 10)

#math:sqrt()

Returns the square root.

math:sqrt(25)    => 5
math:sqrt(2)     => 1.4142135623730951
math:sqrt(0)     => 0

C# equivalent: Math.Sqrt(25)

#Trigonometric

All angles are in radians.

#math:sin(), math:cos(), math:tan()

math:sin(0)              => 0
math:sin(math:pi() div 2) => 1
math:cos(0)              => 1
math:cos(math:pi())      => -1
math:tan(0)              => 0

C# equivalent: Math.Sin(x), Math.Cos(x), Math.Tan(x)

#math:asin(), math:acos(), math:atan()

Inverse trigonometric functions.

math:asin(1)   => 1.5707963... (: π/2 :)
math:acos(1)   => 0
math:atan(1)   => 0.7853981... (: π/4 :)

C# equivalent: Math.Asin(x), Math.Acos(x), Math.Atan(x)

#math:atan2()

Two-argument arctangent — returns the angle in radians between the positive x-axis and the point (x, y).

math:atan2(1, 1)    => 0.7853981... (: π/4 = 45° :)
math:atan2(0, -1)   => 3.1415926... (: π = 180° :)

C# equivalent: Math.Atan2(y, x)

Note: Parameter order is atan2($y, $x), same as in C#.