Involving cos-1((z2+a)1/2/z)
Involving cos-1((z2-1)1/2/z) and cosh-1(1/z)
Involving cos-1((z2+1)1/2/z) and cosh-1(1+2 z-2)
Involving cos-1((z2+1)1/2/z) and cosh-1((1+1/z2)1/2)
