Show that the equation is not an identity by finding a value of x for which both sides are defined but not equal.
-$$\frac { \sin 3 x + \sin 9 x } { \cos 9 x - \cos 3 x } = ?$$

A) $- \cot 3 x$
B) $\tan 3 x + \tan 9 x$
C) $\cot 3 x$
D) $\tan 6 x$

Question

Show that the equation is not an identity by finding a value of x for which both sides are defined but not equal.
-$$\frac { \sin 3 x + \sin 9 x } { \cos 9 x - \cos 3 x } = ?$$

A) $- \cot 3 x$ 
B) $\tan 3 x + \tan 9 x$ 
C) $\cot 3 x$ 
D) $\tan 6 x$

Quizplus · Accepted Answer

The Answer of Show that the equation is not an identity by finding a value of x for which both sides are defined but not equal.
-$$\frac { \sin 3 x + \sin 9 x } { \cos 9 x - \cos 3 x } = ?$$

A) $- \cot 3 x$ 
B) $\tan 3 x + \tan 9 x$ 
C) $\cot 3 x$ 
D) $\tan 6 x$

Show That the Equation Is Not an Identity by Finding sin⁡3x+sin⁡9xcos⁡9x−cos⁡3x=?\frac { \sin 3 x + \sin 9 x } { \cos 9 x - \cos 3 x } = ?cos9x−cos3xsin3x+sin9x​=?

Show That the Equation Is Not an Identity by Finding $\frac { \sin 3 x + \sin 9 x } { \cos 9 x - \cos 3 x } = ?$