CAIE P1 2011 November — Question 4 5 marks

Exam BoardCAIE
ModuleP1 (Pure Mathematics 1)
Year2011
SessionNovember
Marks5
PaperDownload PDF ↗
Mark schemeDownload PDF ↗
TopicCurve Sketching
TypeCurve from derivative information
DifficultyModerate -0.8 This is a straightforward integration question requiring students to find a stationary point by setting f'(x)=0, then integrate to find f(x) and use the range condition to determine the constant. All steps are routine calculus techniques with no problem-solving insight needed, making it easier than average.
Spec1.07n Stationary points: find maxima, minima using derivatives1.08a Fundamental theorem of calculus: integration as reverse of differentiation

4 A function f is defined for \(x \in \mathbb { R }\) and is such that \(\mathrm { f } ^ { \prime } ( x ) = 2 x - 6\). The range of the function is given by \(\mathrm { f } ( x ) \geqslant - 4\).
  1. State the value of \(x\) for which \(\mathrm { f } ( x )\) has a stationary value.
  2. Find an expression for \(\mathrm { f } ( x )\) in terms of \(x\).

Question 4:
Part (i):
AnswerMarks Guidance
Answer/WorkingMarks Guidance
\(3\)B1 [1]
Part (ii):
AnswerMarks Guidance
Answer/WorkingMarks Guidance
\(f(x) = x^2 - 6x(+c)\)M1A1 Dependent on \(c\) present
Subst \((3, -4)\)M1 cao
\(c = 5 \to f(x) = x^2 - 6x + 5\)A1 [4]
## Question 4:

### Part (i):

| Answer/Working | Marks | Guidance |
|---|---|---|
| $3$ | B1 | [1] |

### Part (ii):

| Answer/Working | Marks | Guidance |
|---|---|---|
| $f(x) = x^2 - 6x(+c)$ | M1A1 | Dependent on $c$ present |
| Subst $(3, -4)$ | M1 | cao |
| $c = 5 \to f(x) = x^2 - 6x + 5$ | A1 | [4] |

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4 A function f is defined for $x \in \mathbb { R }$ and is such that $\mathrm { f } ^ { \prime } ( x ) = 2 x - 6$. The range of the function is given by $\mathrm { f } ( x ) \geqslant - 4$.\\
(i) State the value of $x$ for which $\mathrm { f } ( x )$ has a stationary value.\\
(ii) Find an expression for $\mathrm { f } ( x )$ in terms of $x$.

\hfill \mbox{\textit{CAIE P1 2011 Q4 [5]}}