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Vector dot product homework help?
if A = 2i^+6k^
B=6i^+5j^
find A.B
if A.B=0 then what do u conclude from it?
one more question
if A = 6i^+9k^
and B=-4i^+4j^
then find A+B,A-B,A.B
1 Answer
- bonoboLv 71 decade agoFavorite Answer
A • B = (2i + 0j + 6k) • (6i + 5j + 0k)
A • B = 12i² + 10ij + 0 + 0 + 0 + 0 + 36ik + 30jk + 0
All interplanar dot products (ij, ik, jk) = 0 since cos[90º] = 0
A • B = 12i² = -12
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If A • B = 0 , then A and B are perpendicular
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A − B = (6i + 0j + 9k) − (-4i + 4j + 0k)
A − B = 6i + 0j + 9k + 4i − 4j − 0k
A − B = 10i − 4j + 9k
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A + B and A • B are similar