acoshm matrix hyperbolic inverse cosine

## Syntax

    t = acoshm(x)

## Arguments

x, t

  a real or complex square matrix.

## Description

`acoshm` is the matrix hyperbolic inverse cosine of the matrix `x`. Uses the formula `t=logm(x+(x+eye())*sqrtm((x-eye())/(x+eye())))`. For non-symmetric matrices result may be inaccurate.

## Examples

    A=[1,2;3,4];
    coshm(acoshm(A))
    A(1,1)=A(1,1)+%i;
    coshm(acoshm(A))

## See also

- acosh
- logm
- sqrtm