InterviewSolution
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InterviewSolution
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It is found that `|A+B|=|A|`,This necessarily implies.A. B=0B. A, B are antiparallelC. A, B are perpendicularD. `A.B le 0` |
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Answer» Correct Answer - A::B Given that `" " |A+B|=|A| or |A+B|^(2)=|A|^(2)` `rArr " " |A|^(2)+|B|^(2)+2|A||B|cos theta=|A|^(2)` where `theta` is angle between A and B. `rArr " " |B|(|B|+2|A|cos theta)=0` `rArr " " |B|=0 or |B|+2|A|cos theta=0` `rArr " " cos theta =-(|B|)/(2|A|)` If A and B are antiparallel, then `theta=180^(@)` Hence , from Eq. (i) `-1=-(|B|)/(2|A|)rArr |B|=2|A|` Hence, correct answer will be either |B|=0 or B are antiparallel provided |B|=2|A| |
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