Complex arg-trig functions

[Stephen Montgomery-Smith]

One more thing I would like an opinion on.

In my code I check for |z| being small, and then use the approximations:
casinh(z) = z
cacos(z) = Pi - z
catanh(z) = z

However these approximations are not used in the papers by Hull et al, 
and the code works just fine if I don't include these in the code.

The only reason I put this code in is because I thought it would go a 
little faster in the cases that |z| is small.  Checking |z| is small 
takes no time at all.

So what do you think?  Should I keep these in the code or not?

Thanks, Stephen