Three ants A, B and C are crawling on a large horizontal tabletop always occupying vertices of an equilateral triangle, size of which may vary with time. If at an instant, speeds of A and B are vA and vB, prove that vC>= vA+vB.
Well, that's what I don't understand- to always maintain the shape of an equilateral triangle, one of the paths they may acquire is constantly approach each other.
The Attempt at a Solution
First I considered them to move along the equilateral triangle- but using cosine law doesn't help. If they approach each other, I got the relation that their velocities must be equal since:
We write the
What to do now in order to make a solid conclusion?