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Examveda

The value of cot 10°.cot 20°.cot 60°.cot 70°.cot 80° is?

A. 1

B. -1

C. $$\sqrt 3 $$

D. $$\frac{1}{{\sqrt 3 }}$$

Answer: Option D

Solution(By Examveda Team)

cot10° .cot20° .cot60°.cot70° .cot80°
[ In cot A.cot B if A + B = 90° then cot A.cot B = 1 ]
(cot10° .cot80°) × (cot20°.cot70°) × cot60°
∴ 1 × 1 × $$\frac{1}{{\sqrt 3 }}$$
= $$\frac{1}{{\sqrt 3 }}$$

This Question Belongs to Arithmetic Ability >> Trigonometry

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