Determine Which of the Following Are Trigonometric Identities $\frac { \cos ( 4 x ) + \cos ( 2 x ) } { 2 \cot ( 3 x ) } = \cot ( x )$

question 9

Multiple Choice

Determine which of the following are trigonometric identities.
I. $\frac { \cos ( 4 x ) + \cos ( 2 x ) } { 2 \cot ( 3 x ) } = \cot ( x )$
II. $\frac { \cos ( 4 x ) + \cos ( x ) } { \sin ( 3 x ) - \sin ( x ) } = \cot ( 2 x )$
III. $\frac { \cos ( 6 x ) + \cos ( 2 x ) } { \sin ( 4 x ) + \sin ( 2 x ) } = \cot ( 3 x )$

• A) III is the only identity.
• B) I and III are the only identities.
• C) None are identities.
• D) II is the only identity.
• E) I and II are the only identities.

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