This module is always available. It provides access to mathematical functions for complex numbers. The functions are:

(`acos``x`)-
Return the arc cosine of
`x`.

(`acosh``x`)-
Return the hyperbolic arc cosine of
`x`.

(`asin``x`)-
Return the arc sine of
`x`.

(`asinh``x`)-
Return the hyperbolic arc sine of
`x`.

(`atan``x`)-
Return the arc tangent of
`x`.

(`atanh``x`)-
Return the hyperbolic arc tangent of
`x`.

(`cos``x`)-
Return the cosine of
`x`.

(`cosh``x`)-
Return the hyperbolic cosine of
`x`.

(`exp``x`)-
Return the exponential value
`e**`

.`x`

(`log``x`)-
Return the natural logarithm of
`x`.

(`log10``x`)-
Return the base-10 logarithm of
`x`.

(`sin``x`)-
Return the sine of
`x`.

(`sinh``x`)-
Return the hyperbolic sine of
`x`.

(`sqrt``x`)-
Return the square root of
`x`.

(`tan``x`)-
Return the tangent of
`x`.

(`tanh``x`)-
Return the hyperbolic tangent of
`x`.

The module also defines two mathematical constants:

`pi`-
The mathematical constant
*pi*, as a real.

`e`-
The mathematical constant
*e*, as a real.

Note that the selection of functions is similar, but not identical, to
that in module `math` . The reason for having
two modules is that some users aren't interested in complex numbers,
and perhaps don't even know what they are. They would rather have
`math.sqrt(-1)`

raise an exception than return a complex number.
Also note that the functions defined in `cmath` always return a
complex number, even if the answer can be expressed as a real number
(in which case the complex number has an imaginary part of zero).