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If A=pi/6 and B=pi/3, ten consider the f...

If `A=pi/6 and B=pi/3`, ten consider the following statements:
I. sin A + sin B = cos A + cos B
II. Tan A + tan B = cot A + cot B
Which of the above statements is//are correct?

A

Only I

B

Only II

C

Both I and II

D

Neither I nor II

Text Solution

AI Generated Solution

The correct Answer is:
To solve the problem, we need to evaluate the two statements given the angles \( A = \frac{\pi}{6} \) (which is 30 degrees) and \( B = \frac{\pi}{3} \) (which is 60 degrees). ### Step 1: Evaluate Statement I Statement I: \( \sin A + \sin B = \cos A + \cos B \) 1. **Calculate \( \sin A \) and \( \sin B \)**: - \( \sin A = \sin\left(\frac{\pi}{6}\right) = \sin(30^\circ) = \frac{1}{2} \) - \( \sin B = \sin\left(\frac{\pi}{3}\right) = \sin(60^\circ) = \frac{\sqrt{3}}{2} \) 2. **Sum \( \sin A + \sin B \)**: \[ \sin A + \sin B = \frac{1}{2} + \frac{\sqrt{3}}{2} = \frac{1 + \sqrt{3}}{2} \] 3. **Calculate \( \cos A \) and \( \cos B \)**: - \( \cos A = \cos\left(\frac{\pi}{6}\right) = \cos(30^\circ) = \frac{\sqrt{3}}{2} \) - \( \cos B = \cos\left(\frac{\pi}{3}\right) = \cos(60^\circ) = \frac{1}{2} \) 4. **Sum \( \cos A + \cos B \)**: \[ \cos A + \cos B = \frac{\sqrt{3}}{2} + \frac{1}{2} = \frac{1 + \sqrt{3}}{2} \] 5. **Compare the sums**: \[ \sin A + \sin B = \cos A + \cos B \] Thus, Statement I is **true**. ### Step 2: Evaluate Statement II Statement II: \( \tan A + \tan B = \cot A + \cot B \) 1. **Calculate \( \tan A \) and \( \tan B \)**: - \( \tan A = \tan\left(\frac{\pi}{6}\right) = \tan(30^\circ) = \frac{1}{\sqrt{3}} \) - \( \tan B = \tan\left(\frac{\pi}{3}\right) = \tan(60^\circ) = \sqrt{3} \) 2. **Sum \( \tan A + \tan B \)**: \[ \tan A + \tan B = \frac{1}{\sqrt{3}} + \sqrt{3} \] 3. **Calculate \( \cot A \) and \( \cot B \)**: - \( \cot A = \cot\left(\frac{\pi}{6}\right) = \cot(30^\circ) = \sqrt{3} \) - \( \cot B = \cot\left(\frac{\pi}{3}\right) = \cot(60^\circ) = \frac{1}{\sqrt{3}} \) 4. **Sum \( \cot A + \cot B \)**: \[ \cot A + \cot B = \sqrt{3} + \frac{1}{\sqrt{3}} \] 5. **Compare the sums**: \[ \tan A + \tan B = \cot A + \cot B \] Both expressions simplify to the same value, thus Statement II is also **true**. ### Conclusion Both statements are correct. ### Final Answer Both statements I and II are correct. ---
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