Question

Evaluate: tan 5°tan 25°tan 60°tan 65°tan 85°​

Answer 1

Answer:

√3

Step-by-step explanation:

tan 5° can be written as tan(90°-85°)=cot 85°

also, tan 25° can be written as tan(90°-65°)=cot 65°

hence, cot 85°cot 65°tan 60°tan 65tan85 equals to tan 60°

as cot 85=1/tan85 and cot 65=1/tan65

(they will get cancel out)

at last we are only left with tan 60=√3