Question

Prove that tan 70° - tan 20° = 2 tan 50°​

Answer 1

Step-by-step explanation:

$\tan(70) = \tan(50 + 20) \\ \\ \\ \tan(70) = \frac{ \tan(50) + \tan(20) }{1 - \tan(50) \tan(20) } \\ \\ \\ \tan(70) - \tan(70) \tan(50) \tan(20) = \tan(50) + \tan(20) \\ \\ \\ \tan(70) - \tan(50) = \tan(50) + \tan(20) \\ \\ \\ \tan(70) - \tan(20) = 2 \tan(50)$

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