Involving sech-1(1-z/1+z)
Involving sech-1(1-z/1+z) and cot-1((-z)1/2)
Involving sech-1(1-z/1+z) and cot-1(1/(-z)1/2)
Involving sech-1(1-z/1+z) and cot-1((-1/z)1/2)