Functions

Math Functions

XPath math functions — trigonometry, logarithms, exponents, and constants

#Math Functions

The math: namespace provides mathematical functions beyond basic arithmetic.

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

For .NET developers: the math: namespace maps directly to System.Math. math:pi maps to Math.PI. math:e maps to Math.E. math:exp maps to Math.Exp. math:exp10 maps to Math.Pow(10, x). math:log maps to Math.Log. math:log10 maps to Math.Log10. math:pow maps to Math.Pow. math:sqrt maps to Math.Sqrt. math:sin, math:cos, and math:tan map to Math.Sin, Math.Cos, and Math.Tan. math:asin, math:acos, and math:atan map to Math.Asin, Math.Acos, and Math.Atan. math:atan2 maps to Math.Atan2, with the same (y, x) parameter order.

#Constants

#math:pi()

Returns the value of π.

math:pi()   => 3.141592653589793
                                    

#math:e()

Returns Euler's number. New in XPath 4.0.

math:e()   => 2.718281828459045
                                      

#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
                                        

#math:exp10()

Returns 10 raised to the given power.

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

#math:log()

Returns the natural logarithm (base e).

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

#math:log10()

Returns the base-10 logarithm.

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

#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 :)
                                                

#math:sqrt()

Returns the square root.

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

#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
                                                    

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

These are the inverse trigonometric functions.

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

#math:atan2()

This is the two-argument arctangent. It 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° :)
                                                        

Note: The parameter order is atan2($y, $x).