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