CAIE P2 2008 June — Question 2 4 marks

Exam BoardCAIE
ModuleP2 (Pure Mathematics 2)
Year2008
SessionJune
Marks4
PaperDownload PDF ↗
Mark schemeDownload PDF ↗
TopicExponential Equations & Modelling
TypeSimple exponential equation solving
DifficultyModerate -0.8 This is a straightforward exponential equation requiring a standard technique (taking logarithms of both sides, applying log laws, and rearranging to isolate x). It's a single-step problem with no conceptual difficulty beyond knowing the basic method, making it easier than average but not trivial since it requires proper application of logarithm properties.
Spec1.06f Laws of logarithms: addition, subtraction, power rules1.06g Equations with exponentials: solve a^x = b

2 Use logarithms to solve the equation \(4 ^ { x } = 2 \left( 3 ^ { x } \right)\), giving your answer correct to 3 significant figures.

AnswerMarks
Use law for the logarithm of a product, a quotient or a powerM1*
Obtain \(x\ln 4 = \ln 2 + x\ln 3\), or equivalentA1
Solve for \(x\)M1 (dep*)
Obtain answer \(x = 2.41\)A1
[4]
Use law for the logarithm of a product, a quotient or a power | M1* |
Obtain $x\ln 4 = \ln 2 + x\ln 3$, or equivalent | A1 |
Solve for $x$ | M1 (dep*) |
Obtain answer $x = 2.41$ | A1 |
| [4] |
2 Use logarithms to solve the equation $4 ^ { x } = 2 \left( 3 ^ { x } \right)$, giving your answer correct to 3 significant figures.

\hfill \mbox{\textit{CAIE P2 2008 Q2 [4]}}