SOLUTION: Let CC and DD be points with position vectors c and d respectively. If |c|=5, |d|=7 and c⋅d=4, find vector|CD| How can i handle this problem? Thank you so much

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Question 1041269: Let CC and DD be points with position vectors c and d respectively. If |c|=5, |d|=7 and c⋅d=4, find vector|CD|
How can i handle this problem?
Thank you so much
Answer by robertb(5830)   (Show Source): You can put this solution on YOUR website!
Let vector c = OC be (a,b) and let vector d = OD be (r,s)
==> vector CD is (r-a, s-b).
Now , and .
Also, c*d = 4 ==> ar + bs = 4 ==> 2ar + 2bs = 8
==>
=
=.
But , and
therefore..
.
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