CAIE P1 2016 November — Question 6 7 marks

Exam BoardCAIE
ModuleP1 (Pure Mathematics 1)
Year2016
SessionNovember
Marks7
PaperDownload PDF ↗
Mark schemeDownload PDF ↗
TopicStraight Lines & Coordinate Geometry
TypeCoordinates from geometric constraints
DifficultyModerate -0.3 This is a straightforward coordinate geometry problem requiring midpoint formula application and perpendicular gradient conditions. Part (i) is routine algebraic manipulation; part (ii) involves setting up two simultaneous equations from given conditions. While multi-step, it uses only standard AS-level techniques with no novel insight required, making it slightly easier than average.
Spec1.03a Straight lines: equation forms y=mx+c, ax+by+c=01.03b Straight lines: parallel and perpendicular relationships

Three points, \(A\), \(B\) and \(C\), are such that \(B\) is the mid-point of \(AC\). The coordinates of \(A\) are \((2, m)\) and the coordinates of \(B\) are \((n, -6)\), where \(m\) and \(n\) are constants.
  1. Find the coordinates of \(C\) in terms of \(m\) and \(n\). [2]
The line \(y = x + 1\) passes through \(C\) and is perpendicular to \(AB\).
  1. Find the values of \(m\) and \(n\). [5]

Question 6:

AnswerMarks
6 (i)2+x
=n ⇒ x=2n−2
2
m+ y
=−6 ⇒ y=−12−m
AnswerMarks Guidance
2B1
B1[2] No MR for (½(2+n),
½(m – 6))
Expect (2n−2, −12−m)
AnswerMarks Guidance
Page 5Mark Scheme Syllabus
Cambridge International AS/A Level – October/November 20169709 13
(ii)Sub their x, y into y= x+1 → −12−m=2n−2+1
m+6
=−1 oe Not nested in an equation
2−n
Eliminate a variable
AnswerMarks
m=−9, n=−1M1*
B1
DM1
AnswerMarks Guidance
A1A1[5] Expect m+2n=−11
Expect m−n=−8
Note: other methods possible
Question 6:
--- 6 (i) ---
6 (i) | 2+x
=n ⇒ x=2n−2
2
m+ y
=−6 ⇒ y=−12−m
2 | B1
B1 | [2] | No MR for (½(2+n),
½(m – 6))
Expect (2n−2, −12−m)
Page 5 | Mark Scheme | Syllabus | Paper
Cambridge International AS/A Level – October/November 2016 | 9709 | 13
(ii) | Sub their x, y into y= x+1 → −12−m=2n−2+1
m+6
=−1 oe Not nested in an equation
2−n
Eliminate a variable
m=−9, n=−1 | M1*
B1
DM1
A1A1 | [5] | Expect m+2n=−11
Expect m−n=−8
Note: other methods possible
Three points, $A$, $B$ and $C$, are such that $B$ is the mid-point of $AC$. The coordinates of $A$ are $(2, m)$ and the coordinates of $B$ are $(n, -6)$, where $m$ and $n$ are constants.

\begin{enumerate}[label=(\roman*)]
\item Find the coordinates of $C$ in terms of $m$ and $n$. [2]
\end{enumerate}

The line $y = x + 1$ passes through $C$ and is perpendicular to $AB$.

\begin{enumerate}[label=(\roman*)]
\setcounter{enumi}{1}
\item Find the values of $m$ and $n$. [5]
\end{enumerate}

\hfill \mbox{\textit{CAIE P1 2016 Q6 [7]}}