Question

Given that `vec(A)+vec(B)=vec(R)` and `vec(A)+2vec(B)` is perpendicular to `vec(A)` . Then :-
A. 2B=R
B. B=2R
C. B=R
D. `B^(2)=2R^(2)`

Answer 1

Correct Answer - C
`vec(A)+2vec(B)=(vec(R)-vec(B))+2vec(B)=vec(R)+vec(B)`
`vec(A)=(vec(R)-vec(B))`
`(vec(A)+2vec(B)).vec(A)=(vec(R)+vec(B)).(vec(R)-vec(B))=R^(2)-B^(2)=0`
` " "R=B`