$\"\"$

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The vectors are $\"\"$ and $\"\"$ .

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If $\"\"$ and $\"\"$ are orthogonal, then $\"\"$ .

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Find $\"\"$ such that $\"\"$ .

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Dot product definition: $\"\"$ .

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$\"\"$

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Substitute $\"\"$ in the expression.

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$\"\"$

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$\"\"$ .

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$\"\"$

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$\"\"$ .