MCQ
$\sin \frac{\pi}{12}=?$
  • A
    $\frac{(\sqrt{3}+1)}{2 \sqrt{2}}$
  • B
    $\frac{(\sqrt{3}-1)}{2 \sqrt{2}}$
  • C
    $\frac{(2 \sqrt{3}+1)}{2 \sqrt{5}}$
  • D
    $\frac{-(\sqrt{3}-1)}{2}$

Answer

(b) $\frac{(\sqrt{3}-1)}{2 \sqrt{2}}$
Explanation: $\sin \frac{\pi}{12}=\sin \left(\frac{\pi}{4}-\frac{\pi}{6}\right)=\sin \frac{\pi}{4} \cos \frac{\pi}{6}-\cos \frac{\pi}{4} \sin \frac{\pi}{6}$ 
$=\left(\frac{1}{\sqrt{2}} \times \frac{\sqrt{3}}{2}\right)-\left(\frac{1}{\sqrt{2}} \times \frac{1}{2}\right)=\frac{(\sqrt{3}-1)}{2 \sqrt{2}}$

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