Question

A(cosb+cosc-1)+b(cosa+cosc-1)+c(cosa+cosb-1)=0

Answer 1

Answer:

Proved!

Explanation:

Given Problem:

a(cosB+cosC-1)+b(cosC+cosA-1)+c(cosA+cosB-1) = 0​

Solution:

Let ABC be any triangle.

1) Consider the L.H.S (left hand side) of the given equation:

LHS =

We know that,

Projection formula:

= 0 =RHS

(2) Consider the LHS of the given equation:

Hence Proved!!