If a.i=4, then ,what is the value of (axj).(2j-3k) , where a is a vector

Greyson Landry
2022-07-18
Answered

If a.i=4, then ,what is the value of (axj).(2j-3k) , where a is a vector

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yatangije62

Answered 2022-07-19
Author has **16** answers

$a\cdot i=4$ means that $a=4i+sj+tk$ where s and t are real, and so $a\times j=4k-ti$. Now take the dot product with $2j-3k$; I think that pesky t will obligingly vanish.

Bernard Boyer

Answered 2022-07-20
Author has **5** answers

$(a\times \mathbf{j})\cdot (2\mathbf{j}-3\mathbf{k})=a\cdot (\mathbf{j}\times (2\mathbf{j}-3\mathbf{k})=a\cdot (-3\mathbf{i})=(4\mathbf{i})\cdot (-3\mathbf{i})=-12$

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a)

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