Write the Word or Phrase That Best Completes Each Statement $$\frac { \sin x } { \csc x - 1 } + \frac { \sin x } { \csc x + 1 } = 2 \tan ^ { 2 } x$$

Essay

Write the word or phrase that best completes each statement or answers the question.
Establish the identity.
- $$\frac { \sin x } { \csc x - 1 } + \frac { \sin x } { \csc x + 1 } = 2 \tan ^ { 2 } x$$