Question

prove that tanA + tan( 60+A ) + tan ( 120 + A ) = 3tan3A

Answer 1

first simplify
tan( 60+A ) + tan ( 120 + A )

Answer 2

did, and got tanA - 3+ tan^2 A / 1 - 3tan^2A

Answer 3

near to the correct answer ?

Answer 4

If I choose A = 10 degrees, then tan(10) + tan(70) + tan(130) is not 3tan(10).
Are you sure the problem is correct?

Answer 5

yes sir, the problem is correct.

Answer 6

If you are asked to solve for A, then it is a different problem.

But the given problem is not true for all A's. I tried A = 10 degrees and the LHS and RHS are not the same.

Answer 7

oh wait. i missed out on 3 there!

Answer 8

its 3tan3A and not 3tanA

Answer 9

Now the problem is correct.

Answer 10

im sorry for making it wrong, so how do u get the solution now ?

Answer 11

Expand the second and third term. Then add all three terms on the LHS and simplify and see what you get.