exponents and logarithms

PHP includes the standard exponential and logarithmic functions, in both base 10 and base e varieties. Unlike with exp() and the base e, there is no single-argument function to raise 10 to a given power, but in its place you can use the two-argument function pow() with 10 as the first argument.

Exponential Functions

Function	Behavior
pow()	Takes two numerical arguments and returns the first argument raised to the power of the second. The value of pow($x, $y) is xy.
exp()	Takes a single argument and raises e to that power. The value of exp($x) is ex.
log()	The “natural log” function. Takes a single argument and returns its base e logarithm. If ey = x, then the value of log($x) is y.
log10()	Takes a single argument and returns its base-10 logarithm. If 10y = x, then the value of log10($x) is y.