OCR FP1 2016 June — Question 4 6 marks

Exam BoardOCR
ModuleFP1 (Further Pure Mathematics 1)
Year2016
SessionJune
Marks6
PaperDownload PDF ↗
Mark schemeDownload PDF ↗
TopicMatrices
TypeMatrix arithmetic operations
DifficultyEasy -1.2 This is a straightforward matrix arithmetic question testing basic operations (scalar multiplication, subtraction, and matrix multiplication) with simple numbers. All three parts are routine calculations requiring only recall of definitions with no problem-solving or conceptual insight needed. Even for Further Maths FP1, this represents below-average difficulty.
Spec4.03a Matrix language: terminology and notation4.03b Matrix operations: addition, multiplication, scalar

4 The matrices \(\mathbf { A } , \mathbf { B }\) and \(\mathbf { C }\) are given by \(\mathbf { A } = \left( \begin{array} { l l l } a & 2 & 3 \end{array} \right) , \mathbf { B } = \left( \begin{array} { l l l } b & 0 & 5 \end{array} \right)\) and \(\mathbf { C } = \left( \begin{array} { r } 6 \\ 4 \\ - 1 \end{array} \right)\). Find
  1. \(5 \mathbf { A } - 3 \mathbf { B }\),
  2. BC,
  3. CA .

Question 4:
Part (i):
AnswerMarks Guidance
AnswerMarks Guidance
\((5a-3b \quad 10 \quad 0)\)B1 2 elements correct, must be a \(1\times3\) matrix (not coordinates)
B13rd element correct
[2]
Part (ii):
AnswerMarks Guidance
AnswerMarks Guidance
\((6b-5)\)M1 Single value
A1Correct answer, must be a matrix
[2]
Part (iii):
AnswerMarks Guidance
AnswerMarks Guidance
\(\begin{pmatrix}6a & 12 & 18\\ 4a & 8 & 12\\ -a & -2 & -3\end{pmatrix}\)M1 Obtain a \(3\times3\) matrix
A1All elements correct
[2]
## Question 4:

### Part (i):

| Answer | Marks | Guidance |
|--------|-------|----------|
| $(5a-3b \quad 10 \quad 0)$ | B1 | 2 elements correct, must be a $1\times3$ matrix (not coordinates) |
| | B1 | 3rd element correct |
| **[2]** | | |

### Part (ii):

| Answer | Marks | Guidance |
|--------|-------|----------|
| $(6b-5)$ | M1 | Single value |
| | A1 | Correct answer, must be a matrix |
| **[2]** | | |

### Part (iii):

| Answer | Marks | Guidance |
|--------|-------|----------|
| $\begin{pmatrix}6a & 12 & 18\\ 4a & 8 & 12\\ -a & -2 & -3\end{pmatrix}$ | M1 | Obtain a $3\times3$ matrix |
| | A1 | All elements correct |
| **[2]** | | |

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4 The matrices $\mathbf { A } , \mathbf { B }$ and $\mathbf { C }$ are given by $\mathbf { A } = \left( \begin{array} { l l l } a & 2 & 3 \end{array} \right) , \mathbf { B } = \left( \begin{array} { l l l } b & 0 & 5 \end{array} \right)$ and $\mathbf { C } = \left( \begin{array} { r } 6 \\ 4 \\ - 1 \end{array} \right)$. Find\\
(i) $5 \mathbf { A } - 3 \mathbf { B }$,\\
(ii) BC,\\
(iii) CA .

\hfill \mbox{\textit{OCR FP1 2016 Q4 [6]}}