If A=<8,−2,9> and B=<5,1,0>, what is A⋅B−||A||||B||?

1 Answer
Faizan B.
Feb 6, 2016

65−√3874≈2.76

Explanation:

Since A∙B=x1x2+y1y2+z1z2, the A∙B term equals (8⋅5)+(−2⋅1)+(9⋅0), which is 38.

Since the magnitude of a vector is given by √x2+y2+z2, the magnitude of A is √82+(−2)2+92, which equals √149.

Likewise, the magnitude of B is √52+12+02, which equals √26

Therefore, the equation A⋅B−||A||||B|| simplifies to 38−√149⋅√26 which further simplifies to 65−√3874, which is approximately 2.76

Related questions
See all questions in Vectors
Impact of this question
1786 views around the world
You can reuse this answer
Creative Commons License