Question

Let A, B and C be the angles of a triangle , Prove that
tan (B+C) + tan (C+A) + tan (A+B) / tan(π-A) + tan(2π-B) + tan(3π-C) = 1

Answer 1

Do u know what is the sum of all angles of the triangle??
A+B+C=?

Answer 2

no

Answer 3

ok,so i will tell you that sum of all the angles of a triangle is 180 degrees or pi radians
that is A+B+C=pi
from this can you find what is (pi-A) ?

Answer 4

cot A ?

Answer 5

so, A+B+C=pi
Thus,
pi-A = B+C