Involving sech-1(21/2/(1-(1+c z2)1/2)1/2)
Involving sech-1(21/2/(1-(1+z2)1/2)1/2) and sec-1(i/z)
Involving sech-1(21/2/(1-(1-z2)1/2)1/2) and sec-1(1/z)