Involving cos-1((z+a)1/2/z1/2)
Involving cos-1((z-1)1/2/z1/2) and cosh-1(1/z1/2)
Involving cos-1((z+1)1/2/z1/2) and cosh-1(1+2/z)
Involving cos-1((z+1)1/2/z1/2) and cosh-1(z+1/z1/2)