SOLUTION: Let u and v be the vectors of length 3 and 5, respectively. Suppose u . v = 8. Find (-3u+4v) . (2u+5v).
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Question 1016874: Let u and v be the vectors of length 3 and 5, respectively. Suppose u . v = 8. Find (-3u+4v) . (2u+5v). Answer by robertb(5830) (Show Source):
You can put this solution on YOUR website! u*u = square of the length of vector u, and
v*V = square of the length of vector v.
==> (-3u+4v)*(2u+5v) = -6u*u-15u*v+8u*v+20v*v = -6*9 - 15*8 +8*8 +20*25 = 390.
