acosh
Inverse hyperbolic cosine.
y=acosh(x)
Inputs
x An array of real or complex numbers.
Outputs
y An array of same size as x . Each element of the output is the inverse hyperbolic cosine of the corresponding element of the input.


Example
>>x=randn(3,2);
>>x
    2.2735   -0.8460
   -0.0235   -1.2652
   -2.5353    1.0707

>>z=cosh(x);
>>y=acosh(z);
>>y
    2.2735    0.8460
    0.0235    1.2652
    2.5353    1.0707

>>a=complexRandn(2,3)
>>a
   -0.2087 +  0.0796i       0.8024 +  0.4205i      -0.4055 -  0.7543i   
   -1.6297 +  0.4400i       0.6779 +  1.0724i      -0.1423 +  0.0439i   

>>b=cosh(a);
>>c=acosh(b);
>>c
    0.2087 -  0.0796i       0.8024 +  0.4205i       0.4055 +  0.7543i   
    1.6297 -  0.4400i       0.6779 +  1.0724i       0.1423 -  0.0439i