1anyone?
|a|=2,a.b =1,angle between a and b = 60 . r is any vector satisfying:
r.a=2
r.b=8
(r+2a-10b).(a x b) = 4√3
(r+2a-10b) = λ(a x b)
then λ =
A)1/2
B)2
C)1/4
D)4
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6 Answers
33|a||b|cos(600)=1
|b|=1
Let r=la+mb+naxb
(la+mb+naxb).a=2
l|a|2+ma.b=2
4l+m=2
also r.b=8
(la+mb+naxb).b=8
la.b+m|b|2=8
l+m=8
solve for l and m
l=-2 m=10
also
(r+2a-10b).(a x b) = 4√3
(-2a+10b+naxb+2a-10b).(axb) = 4√3 ..putting value of l and m
n|(axb)|2=4√3
n(√3)2=4√3
n=4√3/3
λ=4√3/3
none matching... may be some calculation mistake
33but i can find no mistake in this.. may be options wrong... :O