These mathematical functions allow integers as well as floating-point numbers as arguments.

- Function:
**sin**`arg`¶ - Function:
**cos**`arg`¶ - Function:
**tan**`arg`¶ These are the basic trigonometric functions, with argument

`arg`measured in radians.

- Function:
**asin**`arg`¶ The value of

`(asin`

is a number between −pi/2 and pi/2 (inclusive) whose sine is`arg`)`arg`. If`arg`is out of range (outside [−1, 1]),`asin`

returns a NaN.

- Function:
**acos**`arg`¶ The value of

`(acos`

is a number between 0 and pi (inclusive) whose cosine is`arg`)`arg`. If`arg`is out of range (outside [−1, 1]),`acos`

returns a NaN.

- Function:
**atan**`y &optional x`¶ The value of

`(atan`

is a number between −pi/2 and pi/2 (exclusive) whose tangent is`y`)`y`. If the optional second argument`x`is given, the value of`(atan y x)`

is the angle in radians between the vector`[`

and the`x`,`y`]`X`

axis.

- Function:
**exp**`arg`¶ This is the exponential function; it returns

*e*to the power`arg`.

- Function:
**log**`arg &optional base`¶ This function returns the logarithm of

`arg`, with base`base`. If you don’t specify`base`, the natural base*e*is used. If`arg`or`base`is negative,`log`

returns a NaN.

- Function:
**expt**`x y`¶ This function returns

`x`raised to power`y`. If both arguments are integers and`y`is nonnegative, the result is an integer; in this case, overflow signals an error, so watch out. If`x`is a finite negative number and`y`is a finite non-integer,`expt`

returns a NaN.

- Function:
**sqrt**`arg`¶ This returns the square root of

`arg`. If`arg`is finite and less than zero,`sqrt`

returns a NaN.

In addition, Emacs defines the following common mathematical constants:

- Variable:
**float-e**¶ The mathematical constant

*e*(2.71828…).

- Variable:
**float-pi**¶ The mathematical constant

*pi*(3.14159…).