Question

Show that, tan7.tan14.tan21.tan69.tan76.tan83 = 1​

Answer 1

Step-by-step explanation:

$\tan(7) \tan(14) \tan(21) \tan(69) \tan(76) \tan(83) \\ = \tan(7) \tan(14) \tan(21) \tan(90 - 21) \tan(90 - 14) \tan(90 - 7) \\ = \tan(7) \tan(14) \tan(21) \cot(21) \cot(14) \cot(7) \\ = 1 \times 1 \times 1 \\ = 1 \\ hence \: proved$