InterviewSolution
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InterviewSolution
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Let A,B and C be the unit vectors . Suppose that A.B=A.C =0 and the angle between B and C is `(pi)/(6)` then prove that `A = +-2(BxxC)` |
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Answer» `since ,A.B=O A.C=O` ` Hence , (B+C).A=O` so ,A is perpendicular to (B+C)and A is a unit vector perpendicular to the polane of vector BandC. `A=(BxxC)/(|BxxC|)` `where ,|BxxC|=|B||C|sintheta` ` =|B||c|"sin"(pi)/(6) (therefore sintheta=(pi)/(6))` `=1xx1xx(1)/(2)=(1)/(2)` `A=(BxxC)/(|BxxC|)=+-2(BxxC)` |
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