Question

Which of the following is the correct value of cot 10°.cot 20°.cot 60°. cot 70°. cot 80° ?

• A. 1/√3
• B. √3
• C. -1
• D. 1

Answer 1

Answer:

A. 1/√3

cot A . cot B = 1 ; (A+B = 90°) cot 10 . cot 80 . cot 20. cot 70 . cot 60 = 1 x 1 x 1/√3 = 1/√3