CAIE P3 2004 November — Question 2 4 marks

Exam BoardCAIE
ModuleP3 (Pure Mathematics 3)
Year2004
SessionNovember
Marks4
PaperDownload PDF ↗
Mark schemeDownload PDF ↗
TopicFixed Point Iteration
TypeSolve exponential equation via iteration
DifficultyModerate -0.3 This is a straightforward numerical methods question requiring rearrangement to f(x)=0 form, then applying interval bisection or iteration. The algebraic manipulation is simple (ln(1+x) - ln(x) = 1), and the numerical method is standard bookwork. Slightly easier than average as it's a direct application with no conceptual challenges, though it does require proper execution of the numerical technique.
Spec1.06d Natural logarithm: ln(x) function and properties1.06f Laws of logarithms: addition, subtraction, power rules

2 Solve the equation $$\ln ( 1 + x ) = 1 + \ln x$$ giving your answer correct to 2 significant figures.

AnswerMarks Guidance
Use law for subtraction or addition of logarithms, or the equivalent in exponentialsM1
Use \(\ln e = 1\) or \(e = \exp(1)\)M1
Obtain a correct equation free of logarithms e.g. \(\frac{1+x}{x} = e\) or \(1 + x = ex\)A1
Obtain answer \(x = 0.58\) (allow 0.582 or answer rounding to it)A1 Total: 4 marks
Use law for subtraction or addition of logarithms, or the equivalent in exponentials | M1 | |
Use $\ln e = 1$ or $e = \exp(1)$ | M1 | |
Obtain a correct equation free of logarithms e.g. $\frac{1+x}{x} = e$ or $1 + x = ex$ | A1 | |
Obtain answer $x = 0.58$ (allow 0.582 or answer rounding to it) | A1 | **Total: 4 marks** |
2 Solve the equation

$$\ln ( 1 + x ) = 1 + \ln x$$

giving your answer correct to 2 significant figures.

\hfill \mbox{\textit{CAIE P3 2004 Q2 [4]}}