2. Two vectors, both equal in magnitude, have their resultant equal in magnitude of the either. Find the angle between the two vectors.

OR

Two equal forces have their resultant equal to either, what is the inclination between them?

Let the vectors be x.Thier resultant is also x according to the question.ie it is x.By parallelogram law.

r square = a square+b square+2abcos theta

here,x square = x square + x square +2xxcos theta

ie,x square=2x square+2x squarecos theta

ie,-x square=2x square cos theta

or cos theta= -1/2that is theta =120 degree