OCR Further Additional Pure AS 2024 June — Question 2 6 marks

Exam BoardOCR
ModuleFurther Additional Pure AS (Further Additional Pure AS)
Year2024
SessionJune
Marks6
PaperDownload PDF ↗
Mark schemeDownload PDF ↗
TopicVector Product and Surfaces
TypeConditions for vector product to be zero
DifficultyStandard +0.3 This is a straightforward Further Maths vector product question with two standard parts: (a) computing a cross product and finding triangle area using the formula ½|aƗb|, and (b) setting up three equations from aƗb=0 and solving for Ī». Both parts are routine applications of vector product techniques with no conceptual challenges or novel problem-solving required.
Spec4.04g Vector product: a x b perpendicular vector8.04a Vector product: definition, magnitude/direction, component form8.04c Areas using vector product: triangles and parallelograms

2 The points \(A\) and \(B\) have position vectors \(\mathbf { a }\) and \(\mathbf { b }\) relative to the origin \(O\). It is given that \(\mathbf { a } = \left( \begin{array} { c } 2 \\ 4 \\ 3 \lambda \end{array} \right)\) and \(\mathbf { b } = \left( \begin{array} { r } \lambda \\ - 4 \\ 6 \end{array} \right)\), where \(\lambda\) is a real parameter.
  1. In the case when \(\lambda = 3\), determine the area of triangle \(O A B\).
  2. Determine the value of \(\lambda\) for which \(\mathbf { a } \times \mathbf { b } = \mathbf { 0 }\).

Question 2:
AnswerMarks Guidance
2(a) š‘¢ = = 3(n + 5)2 + 3(n + 5) + 7 = 3n2 + 33n + 97=
š‘› + 5
= 3n2 + 3n + 7 (mod 10)  š‘¢ (mod 10)
AnswerMarks
š‘›M1
A1
AnswerMarks
[2]3.1a
1.1Expanding and considering at least one term mod 10
or evaluating š‘¢ from n=1 to n=10
š‘›
Correct conclusion from correct algebraic work
AnswerMarks Guidance
2(b) The sequence is periodic (with period 5)
Any shorter periodicity would have to be a factor of 5. Since
the sequence is not constant, there are no smaller
AnswerMarks
possibilities.B1
B1
AnswerMarks
[2]1.1
2.4Allow repeating/cyclic
Allow statement only that sequence is non-constant or
sight of {3, 5, (3, 7, 7, …)}.
Question 2:
2 | (a) | š‘¢ = = 3(n + 5)2 + 3(n + 5) + 7 = 3n2 + 33n + 97=
š‘› + 5
= 3n2 + 3n + 7 (mod 10)  š‘¢ (mod 10)
š‘› | M1
A1
[2] | 3.1a
1.1 | Expanding and considering at least one term mod 10
or evaluating š‘¢ from n=1 to n=10
š‘›
Correct conclusion from correct algebraic work
2 | (b) | The sequence is periodic (with period 5)
Any shorter periodicity would have to be a factor of 5. Since
the sequence is not constant, there are no smaller
possibilities. | B1
B1
[2] | 1.1
2.4 | Allow repeating/cyclic
Allow statement only that sequence is non-constant or
sight of {3, 5, (3, 7, 7, …)}.
2 The points $A$ and $B$ have position vectors $\mathbf { a }$ and $\mathbf { b }$ relative to the origin $O$. It is given that $\mathbf { a } = \left( \begin{array} { c } 2 \\ 4 \\ 3 \lambda \end{array} \right)$ and $\mathbf { b } = \left( \begin{array} { r } \lambda \\ - 4 \\ 6 \end{array} \right)$, where $\lambda$ is a real parameter.
\begin{enumerate}[label=(\alph*)]
\item In the case when $\lambda = 3$, determine the area of triangle $O A B$.
\item Determine the value of $\lambda$ for which $\mathbf { a } \times \mathbf { b } = \mathbf { 0 }$.
\end{enumerate}

\hfill \mbox{\textit{OCR Further Additional Pure AS 2024 Q2 [6]}}