Involving cosh-1((((1-z2)1/2-1)/(2(1-z2)1/2))1/2)
Involving cosh-1((((1-z2)1/2-1)/(2(1-z2)1/2))1/2) and coth-1(z)
Involving cosh-1((((1-z2)1/2-1)/(2(1-z2)1/2))1/2) and coth-1(1/z)