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28 votes
28 votes
1. Find u, if u= (1-3) (1 point) . O (1, -1) o (4-1) O (3,-9) O (1.-9)

User Artooras
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1 Answer

24 votes
24 votes

Remember the following formula for the scalar multiplication of a number times a vector.

Let v be a vector such that v = (a,b), and let k be a real number. Then:


k\vec{v}=k(a,b)=(ka,kb)

If u=(1,-3), then:


\begin{gathered} (1)/(3)\vec{u}=(1)/(3)(1,-3) \\ =((1)/(3)*1,(1)/(3)*-3) \\ =((1)/(3),-1) \end{gathered}

Therefore, the answer is option B:


((1)/(3),-1)

User Nisha Dave
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