Vector Arithmetic — Question 10

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Question 10

Find constants a,ba,b so that a⟨1,1,0⟩+b⟨0,1,1⟩=⟨2,5,3⟩a\langle1,1,0\rangle+b\langle0,1,1\rangle=\langle2,5,3\rangle, or prove it is impossible.

Original worksheet page 1: question and worked solution for 5-2-010
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Question 10 – Solution

Write every vector in matching component order. Perform scalar multiplication before addition or subtraction, then interpret the resulting components in the context of the problem.

See the diagram in the original worksheet below.

The linear combination is ⟨a,a+b,b⟩\langle a,a+b,b\rangle.

The first and third components force a=2a=2 and b=3b=3.

Then a+b=5a+b=5, matching the middle component. Hence a=2,b=3\boxed{a=2,\ b=3}.

The result follows from the defining vector formulas used above, and each component, magnitude, or scalar condition has been checked against the information in the question.

Vector equations behave like ordinary algebra provided that every operation is performed component by component. A final component check is often the fastest verification.

Original worksheet page 2: question and worked solution for 5-2-010

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