Question

prove that tan20°×tan40°×tan60°+tan80°=3​

Answer 1

Step-by-step explanation:

We know that tan3Ф=tanФ*tan(60+Ф)*tan(60-Ф)  (Ф= 20 )

= tan20*tan(60-20)*tan(60+Ф) * tan60

= tan 60 * tan60

= √3*√3

= 3