Trigonometric Identities Question 203

Question: $ \frac{{{\sin }^{2}}A-{{\sin }^{2}}B}{\sin A\cos A-\sin B\cos B} $ is equal to

Options:

A) $ \tan (A-B) $

B) $ \tan (A+B) $

C) $ cot(A-B) $

D) $ cot(A+B) $

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Answer:

Correct Answer: B

Solution:

[b] $ \frac{{{\sin }^{2}}A-{{\sin }^{2}}B}{\sin A\cos A-\sin B\cos B} $ $ =,\frac{2\sin (A+B)sin(A-B)}{\sin 2A-\sin 2B} $ $ =,\frac{2\sin (A+B)sin(A-B)}{2\sin (A-B)cos(A+B)} $ $ =\tan (A+B) $