Write the Word or Phrase That Best Completes Each Statement $$- \tan ^ { 2 } x + \sec ^ { 2 } x = \sec ^ { 2 } x \cos ^ { 2 } x$$

Essay

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