CAIE Further Paper 1 2024 June — Question 6 13 marks

Exam BoardCAIE
ModuleFurther Paper 1 (Further Paper 1)
Year2024
SessionJune
Marks13
PaperDownload PDF ↗
Mark schemeDownload PDF ↗
TopicCurve Sketching
TypeSimple rational function analysis
DifficultyModerate -0.3 This is a straightforward curve sketching question requiring standard techniques: identifying asymptotes (denominator never zero, limit as x→∞), finding stationary points via quotient rule, and reflecting for the y² variant. All steps are routine A-level methods with no novel insight required, though the multi-part structure and Further Maths context place it slightly below average difficulty overall.
Spec1.02m Graphs of functions: difference between plotting and sketching1.02n Sketch curves: simple equations including polynomials1.07n Stationary points: find maxima, minima using derivatives

6 The curve \(C\) has equation \(y = \frac { x + 1 } { x ^ { 2 } + 3 }\).
  1. Show that \(C\) has no vertical asymptotes and state the equation of the horizontal asymptote. [2]
  2. Find the coordinates of any stationary points on \(C\). \includegraphics[max width=\textwidth, alt={}, center]{7eb2abb1-68f4-4cc8-8314-f436906d6c4e-12_2715_35_144_2012} \includegraphics[max width=\textwidth, alt={}, center]{7eb2abb1-68f4-4cc8-8314-f436906d6c4e-13_2718_33_141_23}
  3. Sketch \(C\), stating the coordinates of the intersections with the axes.
  4. Sketch \(y ^ { 2 } = \frac { x + 1 } { x ^ { 2 } + 3 }\), stating the coordinates of the stationary points and the intersections with the axes.

Question 6(a):
AnswerMarks Guidance
AnswerMarks Guidance
\(x^2 + 3 = 0\) has no real rootsB1 OE
\(y = 0\)B1 Horizontal asymptote
Question 6(b):
AnswerMarks Guidance
AnswerMarks Guidance
\(\frac{dy}{dx} = \frac{(x^2+3)-(x+1)(2x)}{(x^2+3)^2}\)M1 Finds \(\frac{dy}{dx}\)
\(x^2 + 2x - 3 = 0\)M1 Sets equal to 0 and simplifies to quadratic equation
\(\left(-3,\ -\frac{1}{6}\right),\ \left(1,\ \frac{1}{2}\right)\)A1 A1
Question 6(c):
AnswerMarks Guidance
AnswerMarks Guidance
Graph with axes and approach to asymptoteB1 Axes and approach to asymptote
Correct smooth shape and positionB1 Correct smooth shape and position
\((-1,\ 0),\ \left(0,\ \frac{1}{3}\right)\)B1 States coordinates of intersections with axes, may be shown on their graph
Question 6(d):
AnswerMarks Guidance
AnswerMarks Guidance
Sections for \(x \geq 0\) and \(x < -1\) correctB1 Sections for \(x \geq 0\) and \(x < -1\) correct
\(-1 \leq x < 0\) correctB1 \(-1 \leq x < 0\) correct
\((-1,\ 0),\ \left(0,\ \pm\frac{1}{\sqrt{3}}\right)\)B1 States coordinates of intersections with axes, may be shown on their graph
\(\left(1,\ \pm\frac{1}{\sqrt{2}}\right)\)B1 May be shown on their graph
## Question 6(a):

| Answer | Marks | Guidance |
|--------|-------|----------|
| $x^2 + 3 = 0$ has no real roots | B1 | OE |
| $y = 0$ | B1 | Horizontal asymptote |

## Question 6(b):

| Answer | Marks | Guidance |
|--------|-------|----------|
| $\frac{dy}{dx} = \frac{(x^2+3)-(x+1)(2x)}{(x^2+3)^2}$ | M1 | Finds $\frac{dy}{dx}$ |
| $x^2 + 2x - 3 = 0$ | M1 | Sets equal to 0 and simplifies to quadratic equation |
| $\left(-3,\ -\frac{1}{6}\right),\ \left(1,\ \frac{1}{2}\right)$ | A1 A1 | |

## Question 6(c):

| Answer | Marks | Guidance |
|--------|-------|----------|
| Graph with axes and approach to asymptote | B1 | Axes and approach to asymptote |
| Correct smooth shape and position | B1 | Correct smooth shape and position |
| $(-1,\ 0),\ \left(0,\ \frac{1}{3}\right)$ | B1 | States coordinates of intersections with axes, may be shown on their graph |

## Question 6(d):

| Answer | Marks | Guidance |
|--------|-------|----------|
| Sections for $x \geq 0$ and $x < -1$ correct | B1 | Sections for $x \geq 0$ and $x < -1$ correct |
| $-1 \leq x < 0$ correct | B1 | $-1 \leq x < 0$ correct |
| $(-1,\ 0),\ \left(0,\ \pm\frac{1}{\sqrt{3}}\right)$ | B1 | States coordinates of intersections with axes, may be shown on their graph |
| $\left(1,\ \pm\frac{1}{\sqrt{2}}\right)$ | B1 | May be shown on their graph |

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6 The curve $C$ has equation $y = \frac { x + 1 } { x ^ { 2 } + 3 }$.
\begin{enumerate}[label=(\alph*)]
\item Show that $C$ has no vertical asymptotes and state the equation of the horizontal asymptote. [2]
\item Find the coordinates of any stationary points on $C$.\\

\includegraphics[max width=\textwidth, alt={}, center]{7eb2abb1-68f4-4cc8-8314-f436906d6c4e-12_2715_35_144_2012}\\
\includegraphics[max width=\textwidth, alt={}, center]{7eb2abb1-68f4-4cc8-8314-f436906d6c4e-13_2718_33_141_23}
\item Sketch $C$, stating the coordinates of the intersections with the axes.
\item Sketch $y ^ { 2 } = \frac { x + 1 } { x ^ { 2 } + 3 }$, stating the coordinates of the stationary points and the intersections with the axes.
\end{enumerate}

\hfill \mbox{\textit{CAIE Further Paper 1 2024 Q6 [13]}}