CAIE P2 2017 June — Question 2 4 marks

Exam BoardCAIE
ModuleP2 (Pure Mathematics 2)
Year2017
SessionJune
Marks4
PaperDownload PDF ↗
Mark schemeDownload PDF ↗
TopicModulus function
TypeSolve |linear| > |linear|
DifficultyStandard +0.3 This is a standard modulus inequality requiring consideration of critical points (x=3/2 and x=4) and case analysis across intervals. While it involves multiple cases and algebraic manipulation, it follows a routine procedure taught in P2 with no novel insight required, making it slightly easier than average.
Spec1.02l Modulus function: notation, relations, equations and inequalities

2 Solve the inequality \(| 4 - x | \leqslant | 3 - 2 x |\).

Question 2:
AnswerMarks Guidance
AnswerMarks Guidance
State or imply non-modulus inequality \((4-x)^2 \leqslant (3-2x)^2\) or corresponding equation, pair of linear equations or linear inequalitiesM1
Attempt solution of 3-term quadratic equation, of two linear equations or of two linear inequalitiesM1
Obtain critical values \(-1\) and \(\frac{7}{3}\)A1 SR Allow B1 for \(x \leqslant -1\) only or \(x \geqslant \frac{7}{3}\) only if first M1 is not given
State answer \(x \leqslant -1,\ x \geqslant \frac{7}{3}\)A1 Do not accept \(\frac{7}{3} \leqslant x \leqslant -1\) or \(-1 \geqslant x \geqslant \frac{7}{3}\) for A1
Total:4
## Question 2:

| Answer | Marks | Guidance |
|--------|-------|----------|
| State or imply non-modulus inequality $(4-x)^2 \leqslant (3-2x)^2$ or corresponding equation, pair of linear equations or linear inequalities | M1 | |
| Attempt solution of 3-term quadratic equation, of two linear equations or of two linear inequalities | M1 | |
| Obtain critical values $-1$ and $\frac{7}{3}$ | A1 | SR Allow B1 for $x \leqslant -1$ only or $x \geqslant \frac{7}{3}$ only if first M1 is not given |
| State answer $x \leqslant -1,\ x \geqslant \frac{7}{3}$ | A1 | Do not accept $\frac{7}{3} \leqslant x \leqslant -1$ or $-1 \geqslant x \geqslant \frac{7}{3}$ for A1 |
| **Total:** | **4** | |
2 Solve the inequality $| 4 - x | \leqslant | 3 - 2 x |$.\\

\hfill \mbox{\textit{CAIE P2 2017 Q2 [4]}}