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Question
If \[\tan A = \frac{1}{7}\] and \[\tan B = \frac{1}{3}\] , show that cos 2A = sin 4B
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Solution
Given:
\[ \Rightarrow \cos2A = \frac{48}{50} \text{ and } \sin4B = \frac{2 \times \frac{3}{4} \times 16}{25}\]
\[ \Rightarrow \cos2A = \frac{24}{25} \text{ and } \sin4B = \frac{24}{25}\]
∴ cos 2A = sin 4B
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