If A=<2,7,−4> and B=<−2,−1,5>, what is A⋅B−||A||||B||?

1 Answer
sankarankalyanam
Jul 5, 2018

−71.2492

Explanation:

Dot Product or Scalar Product
(a1,a2,a3)⋅(b1,b2,b3)=a1b1+a2b2+a3b3

Vector Product =∣∣∣→A∣∣∣⋅∣∣∣→B∣∣∣

![https://sites.google.com/a/g.coppellisd.com/coppell-ib-math/math-sl/topics---sl/vectors/scalar-and-vector-product](useruploads.socratic.org)

→A⋅→B=2⋅−2+7⋅−1+−4⋅5=−31

∣∣∣→A∣∣∣=√22+72+−12=√54

∣∣∣→B∣∣∣=√−22+−12+52=√30

Finally: →A⋅→B−∣∣∣→A∣∣∣⋅∣∣∣→B∣∣∣=−21−√54√30

⇒−31−40.2492=−71.2492

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