Force Question

[cb]

I need help getting in the right direction...

Two forces have the same magnitude F. What is the angle between the two vectors if their sum has a magnitude of 2*F? sqrt(2)*F? zero?

[Pyrrhus]

How about using the triangle vector adition method? and then applying cosine law to it to find the angle between F and F? or better yet use the paralellogram vector adittion method.