cotd element-wise cotangent function, argument in degree

## Syntax

    y = cotd(x)

## Arguments

x

  a real array.

y

  a real array with same dimensions as `x`.

## Description

The entries of `y` are the cotangents of the corresponding entries of `x` supposed to be given in degree. `t=cos(x)./sin(x)`. For entries equal to `n*180` with `n` integer, the results are infinite, whereas `cotg(n*%pi)` is large but finite because `%pi` cannot be represented exactly. For entries equal to `n*90` with `n` integers and odd the results are exactly `0`.

## Examples

    cotd([30 45 60 90])
    cotd([-180 -90 0 90 180])

    --> cotd([30 45 60 90])
     ans  =
       1.7320508   1.   0.5773503   0.

    --> cotd([-180 -90 0 90 180])
     ans  =
       Inf   0.   Inf   0.   Inf

## See also

- cotg
- coth
- tan
- tand