I need some help with the the following problem: If vectors a and b are orthogonal, |a|=3, |b|=4. Calculate: a) p=|(a+b)x(a-b)| b) q=|(3a-b)x(a-2b)|
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Originally Posted by sillyme I need some help with the the following problem: If vectors a and b are orthogonal, |a|=3, |b|=4. Calculate: a) p=|(a+b)x(a-b)| b) q=|(3a-b)x(a-2b)| Is that a cross product ? Or is it a dot product: ? I suspect it is a dot product.
Originally Posted by Plato Is that a cross product ? Or is it a dot product: ? I suspect it is a dot product. It is a cross product. p is the norm of the cross product between the vector sum (a+b) and the vector difference (a-b)
Some useful properties: So: But since they're orthogonal ....
Thank you o_O.
A very simple way to do this is to set up a coordinate system so the and . Then , , , and .
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