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(sin^2A-sin^2B)/(sinAcosA-sinBcosB) is ...

`(sin^2A-sin^2B)/(sinAcosA-sinBcosB)` is equal to
(a) `tan(A-B)`
(b) `"tan"(A+B)`
(c) `cot(A-B)`
(d) `cot(A+B)`

A

`tan(A-B)`

B

`tan(A+B)`

C

`cot(A-B)`

D

`cot(A+B)`

Text Solution

AI Generated Solution

The correct Answer is:
To solve the expression \(\frac{\sin^2 A - \sin^2 B}{\sin A \cos A - \sin B \cos B}\), we can follow these steps: ### Step 1: Use the difference of squares The numerator \(\sin^2 A - \sin^2 B\) can be factored using the difference of squares formula: \[ \sin^2 A - \sin^2 B = (\sin A + \sin B)(\sin A - \sin B) \] ### Step 2: Rewrite the denominator The denominator \(\sin A \cos A - \sin B \cos B\) can be rewritten as: \[ \sin A \cos A - \sin B \cos B = \frac{1}{2} \sin(2A) - \frac{1}{2} \sin(2B) = \frac{1}{2} (\sin(2A) - \sin(2B)) \] Using the sine difference formula, we have: \[ \sin(2A) - \sin(2B) = 2 \cos(A + B) \sin(A - B) \] Thus, the denominator becomes: \[ \sin A \cos A - \sin B \cos B = \frac{1}{2} \cdot 2 \cos(A + B) \sin(A - B) = \cos(A + B) \sin(A - B) \] ### Step 3: Substitute back into the expression Now substituting the factored forms back into the original expression, we have: \[ \frac{(\sin A + \sin B)(\sin A - \sin B)}{\cos(A + B) \sin(A - B)} \] ### Step 4: Simplify the expression Notice that \(\sin A - \sin B\) cancels out: \[ = \frac{\sin A + \sin B}{\cos(A + B)} \] ### Step 5: Use the identity for tangent Using the identity \(\tan \theta = \frac{\sin \theta}{\cos \theta}\), we can express the result as: \[ = \tan(A + B) \] ### Final Result Thus, the expression \(\frac{\sin^2 A - \sin^2 B}{\sin A \cos A - \sin B \cos B}\) simplifies to: \[ \tan(A + B) \] ### Answer The correct option is (b) \(\tan(A + B)\). ---

To solve the expression \(\frac{\sin^2 A - \sin^2 B}{\sin A \cos A - \sin B \cos B}\), we can follow these steps: ### Step 1: Use the difference of squares The numerator \(\sin^2 A - \sin^2 B\) can be factored using the difference of squares formula: \[ \sin^2 A - \sin^2 B = (\sin A + \sin B)(\sin A - \sin B) \] ...
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