OCR MEI Further Pure Core AS 2022 June — Question 2 7 marks

Exam BoardOCR MEI
ModuleFurther Pure Core AS (Further Pure Core AS)
Year2022
SessionJune
Marks7
PaperDownload PDF ↗
Mark schemeDownload PDF ↗
TopicVectors: Lines & Planes
TypeParallel and perpendicular planes
DifficultyStandard +0.3 This is a straightforward Further Maths vectors question testing standard techniques: (a) requires showing a vector is perpendicular to the normal (dot product = 0), and (b) uses the standard formula for angle between planes via their normals. Both parts are direct applications of learned methods with minimal problem-solving required, though the Further Maths context places it slightly above average A-level difficulty.
Spec4.04a Line equations: 2D and 3D, cartesian and vector forms4.04d Angles: between planes and between line and plane

2
  1. Show that the vector \(\mathbf { i } + 4 \mathbf { j } + 2 \mathbf { k }\) is parallel to the plane \(2 \mathrm { x } + \mathrm { y } - 3 \mathrm { z } = 10\).
  2. Determine the acute angle between the planes \(2 x + y - 3 z = 10\) and \(x - y - 3 z = 3\).

Question 2:
AnswerMarks Guidance
2(a) (i + 4j + 2k).( 2i + j − 3k)
= 12 +41 + 2(−3) = 0
so 2i + j − 3k is perpendicular to normal to the plane,
AnswerMarks
hence parallel to the planeM1
A1
A1
AnswerMarks
[3]3.1a
1.1
AnswerMarks
3.2ascalar product of (i + 4j + 2k) and (2i + j − 3k)
= 0
justification given
AnswerMarks Guidance
2(b) ( 2 3 ) .( 3 ) i + j − k − i j − k
c o s  =
2 2 1 2 ( 3 2 ) 2 1 ( 1 ) 2 ( 3 ) 2 + + − + − + −
2 − 1 + 9 1 0
= [ = ]
1 4 1 1 1 4 1 1
AnswerMarks
 = 36.3M1
M1
A1
A1
AnswerMarks
[4]1.1a
1.1
1.1
AnswerMarks
1.1finding angle between normals
formula correct
36 or 0.63 rads or better
Question 2:
2 | (a) | (i + 4j + 2k).( 2i + j − 3k)
= 12 +41 + 2(−3) = 0
so 2i + j − 3k is perpendicular to normal to the plane,
hence parallel to the plane | M1
A1
A1
[3] | 3.1a
1.1
3.2a | scalar product of (i + 4j + 2k) and (2i + j − 3k)
= 0
justification given
2 | (b) | ( 2 3 ) .( 3 ) i + j − k − i j − k
c o s  =
2 2 1 2 ( 3 2 ) 2 1 ( 1 ) 2 ( 3 ) 2 + + − + − + −
2 − 1 + 9 1 0
= [ = ]
1 4 1 1 1 4 1 1
 = 36.3 | M1
M1
A1
A1
[4] | 1.1a
1.1
1.1
1.1 | finding angle between normals
formula correct
36 or 0.63 rads or better
2
\begin{enumerate}[label=(\alph*)]
\item Show that the vector $\mathbf { i } + 4 \mathbf { j } + 2 \mathbf { k }$ is parallel to the plane $2 \mathrm { x } + \mathrm { y } - 3 \mathrm { z } = 10$.
\item Determine the acute angle between the planes $2 x + y - 3 z = 10$ and $x - y - 3 z = 3$.
\end{enumerate}

\hfill \mbox{\textit{OCR MEI Further Pure Core AS 2022 Q2 [7]}}