Question

find the value of cot 10.cot 30.cot 80

Answer 1

Cot10*Cot30*Cot80 = tan80*Cot30*Cot80. {cot(90-@) = tan@}

= Cot30
= √3

Answer 2

cotx= tan(90-x) -equation (1)

cotx.tanx=1 -equation (2)

cot30.[tan(90-10).cot80]
= √3 .(1)
= √3