If `vec(a)` and `vec(b)` are two non-collinear vectors having the same initial point. What are the vectors represented by `vec(a) + vec(b)` and `vec(a) - vec(b)` ?

Prove that |vec(a)-vec(b)|ge|vec(a)|-|vec(b)| .

If vec(a) and vec(b) are the position vectors of vec(A) and vec(B) respectively, then find the position vector of a point vec(C) and vec(BA) produced such that vec(BC) = 1.5 vec(BA) . Also, it is shown by graphically.