Solve the Problem $$\cot ^ { 2 } \frac { u } { 2 } = \frac { \csc u + \cot u } { \csc u - \cot u }$$

Solve the problem.

- $$\cot ^ { 2 } \frac { u } { 2 } = \frac { \csc u + \cot u } { \csc u - \cot u }$$