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Suppose vector u = <3,3,-9> , vector v = <-2,1,8> and vector w =...

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bleeeeee | Student | Honors

Posted January 25, 2013 at 3:12 PM via web

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Suppose vector u = <3,3,-9> , vector v = <-2,1,8> and vector w = <-5,-5,7>

(a) Find (vector v) cross product (vector w)

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sciencesolve | Teacher | (Level 3) Educator Emeritus

Posted January 25, 2013 at 3:21 PM (Answer #1)

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You need to use the following formula to evaluate the cross product of the vectors `bar v` and `bar w` , such that:

`bar v x bar w = [(bar i,bar j,bar k),(-2,1,8),(-5,-5,7)]`

`bar v x bar w = 1*7*bar i + (-2)*(-5)*bar k + 8*(-5)*bar j - 1*(-5)*bar k - 8*(-5)*bar i - 7*(-2)*bar j`

Reducing duplicate terms yields:

`bar v x bar w = 47 bar i - 26 bar j + 15 bar k`

Hence, evaluating the cross product of vectors `bar v` and `bar w` yields `bar v x bar w = 47 bar i - 26 bar j + 15 bar k.`

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