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Evaluate the product (3vec(a)-5vec(b)).(...

Evaluate the product `(3vec(a)-5vec(b)).(2vec(a)+7vec(b))`.

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We have , `(3vec(a)-5vec(a)).(2vec(a)+7vec(b))`.
`=(3a).(2a+7b)-(5vec(b)).(2vec(a)+7vec(b))`
`=6(a.a)+21(a.b)-10(b.a)-35(b.b)`
`6|a|^2+11(a.b)-35|b|^2 (because a.a =|a|^2 and a.b=b.a)`
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SUBHASH PUBLICATION-VECTOR ALGEBRA -TWO MARKS/THREE MARKS QUESTIONS WITH ANSWERS
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