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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…).

Next: Random Numbers, Previous: Bitwise Operations on Integers, Up: Numbers [Contents][Index]