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

Essay

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