OCR MEI C4 2009 January — Question 3 5 marks

Exam BoardOCR MEI
ModuleC4 (Core Mathematics 4)
Year2009
SessionJanuary
Marks5
PaperDownload PDF ↗
Mark schemeDownload PDF ↗
TopicVectors 3D & Lines
TypeLinear combinations of vectors
DifficultyModerate -0.8 This is a straightforward linear combination problem requiring students to set up and solve a simple system of two simultaneous equations in two unknowns by equating coefficients. It's routine practice of a standard technique with no conceptual difficulty or problem-solving insight required, making it easier than average.
Spec1.10b Vectors in 3D: i,j,k notation1.10d Vector operations: addition and scalar multiplication

3 Vectors \(\mathbf { a }\) and \(\mathbf { b }\) are given by \(\mathbf { a } = 2 \mathbf { i } + \mathbf { j } - \mathbf { k }\) and \(\mathbf { b } = 4 \mathbf { i } - 2 \mathbf { j } + \mathbf { k }\).
Find constants \(\lambda\) and \(\mu\) such that \(\lambda \mathbf { a } + \mu \mathbf { b } = 4 \mathbf { j } - 3 \mathbf { k }\).

Question 3:
AnswerMarks Guidance
Answer/WorkingMarks Guidance
\(H = 5+40\tan30°\) or \(H=h+40\tan\theta\)B1 or evaluated
\(V = \frac{1}{5}\pi(H+h) = \frac{1}{5}\pi(10+40\tan30°)\)M1 including substitution of values
\(= 20.8\) litresA1
## Question 3:
| Answer/Working | Marks | Guidance |
|---|---|---|
| $H = 5+40\tan30°$ or $H=h+40\tan\theta$ | B1 | or evaluated |
| $V = \frac{1}{5}\pi(H+h) = \frac{1}{5}\pi(10+40\tan30°)$ | M1 | including substitution of values |
| $= 20.8$ litres | A1 | |
3 Vectors $\mathbf { a }$ and $\mathbf { b }$ are given by $\mathbf { a } = 2 \mathbf { i } + \mathbf { j } - \mathbf { k }$ and $\mathbf { b } = 4 \mathbf { i } - 2 \mathbf { j } + \mathbf { k }$.\\
Find constants $\lambda$ and $\mu$ such that $\lambda \mathbf { a } + \mu \mathbf { b } = 4 \mathbf { j } - 3 \mathbf { k }$.

\hfill \mbox{\textit{OCR MEI C4 2009 Q3 [5]}}