CAIE P2 2018 November — Question 2 5 marks

Exam BoardCAIE
ModuleP2 (Pure Mathematics 2)
Year2018
SessionNovember
Marks5
PaperDownload PDF ↗
Mark schemeDownload PDF ↗
TopicStandard Integrals and Reverse Chain Rule
TypeDefinite integral with logarithmic form
DifficultyModerate -0.8 This is a straightforward application of the standard integral ∫(f'(x)/f(x))dx = ln|f(x)| + c. Students need only recognize that 6/(2x+1) can be written as 3·(2/(2x+1)), evaluate [3ln(2x+1)] from 1 to 7, and simplify 3(ln15 - ln3) = 3ln5 = ln125. It's simpler than average because it requires just one standard technique with minimal algebraic manipulation.
Spec1.06f Laws of logarithms: addition, subtraction, power rules1.08c Integrate e^(kx), 1/x, sin(kx), cos(kx)

2 Show that \(\int _ { 1 } ^ { 7 } \frac { 6 } { 2 x + 1 } \mathrm {~d} x = \ln 125\).

Question 2:
AnswerMarks Guidance
AnswerMarks Guidance
Integrate to obtain form \(k\ln(2x+1)\)M1
Obtain correct \(3\ln(2x+1)\)A1
Use subtraction law of logarithms correctlyM1 Dependent on first M1
Use power law of logarithms correctlyM1 Dependent on first M1
Confirm \(\ln 125\)A1
Total: 5
## Question 2:

| Answer | Marks | Guidance |
|--------|-------|----------|
| Integrate to obtain form $k\ln(2x+1)$ | M1 | |
| Obtain correct $3\ln(2x+1)$ | A1 | |
| Use subtraction law of logarithms correctly | M1 | Dependent on first M1 |
| Use power law of logarithms correctly | M1 | Dependent on first M1 |
| Confirm $\ln 125$ | A1 | |
| **Total: 5** | | |
2 Show that $\int _ { 1 } ^ { 7 } \frac { 6 } { 2 x + 1 } \mathrm {~d} x = \ln 125$.\\

\hfill \mbox{\textit{CAIE P2 2018 Q2 [5]}}