Write the Word or Phrase That Best Completes Each Statement $$\tan ^ { 5 } x = \tan x \left( \sec ^ { 4 } x - 2 \sec ^ { 2 } x + 1 \right)$$

Essay

Write the word or phrase that best completes each statement or answers the question.
Establish the identity.
- $$\tan ^ { 5 } x = \tan x \left( \sec ^ { 4 } x - 2 \sec ^ { 2 } x + 1 \right)$$