Write an expression for magnitude of the resultant vector `.vec(R).` of two vectors `vec(A) and vec(B)` acting at a point. When will this resultant vector `.vec(R).` be maximum ?

Explanation

We have
`" "abs(vec(R))=sqrt(abs(vec(A))^(2)+abs(vec(B))^(2)+2abs(vec(A))abs(vec(B))costheta)`
for max value of `vec(R)`
`" "theta=0^(@)`
Then `" "vec(R)=vec(A)+vec(B)`