$({\alpha }^2+\eta ^)1/2+\mathrm{tfrac}12\alpha \ln \eta -\alpha \ln \left(\right({\alpha }^2+\eta ^)1/2+\alpha )=\mathrm{operatorname}arccos\left(\frac{x}{(1+{\alpha }^2^)1/2}\right)+\frac{\alpha }{2}\ln \left(\frac{1+{\alpha }^2+({\alpha }^2-1)x^2-2\alpha x(1+{\alpha }^2-x^2^)1/2}{(1+{\alpha }^2)(1-x^2)}\right)$