Question

Tan50-tan90=2tan10 prove this

Answer 1

It has been shown that  

Tan (A+B) = tan A + tan B / (1- tanA × tanB)

In the above question;

tan 50 = tan (40 + 10)

Thus;

tan (40 + 10) = tan 40 + tan 10 / (1- tan 40 × tan 10)

The solution for the problem is described in the below image