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

Essay

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