Involving sech^{-1}((2/(1-(1+c z^{2})^{1/2}) )^{1/2})

Involving sech^{-1}((2/(1-(1+z^{2})^{1/2}) )^{1/2}) and cos^{-1}(i z)

Involving sech^{-1}((2/(1-(1-z^{2})^{1/2}) )^{1/2}) and cos^{-1}(z)