OCR C3 — Question 2 7 marks

Exam BoardOCR
ModuleC3 (Core Mathematics 3)
Marks7
PaperDownload PDF ↗
Mark schemeDownload PDF ↗
TopicExponential Equations & Modelling
TypeNatural logarithm equation solving
DifficultyModerate -0.8 Part (i) is a straightforward one-step natural logarithm equation requiring only the definition of ln (exponentiating both sides). Part (ii) asks for a counter-example to disprove a statement, which requires understanding that ln(y) ≥ 0 when y ≥ 1, but this is a routine C3 skill. Both parts are simpler than average A-level questions, requiring minimal problem-solving.
Spec1.01c Disproof by counter example1.06g Equations with exponentials: solve a^x = b

2. (i) Solve the equation $$\ln ( 3 x + 1 ) = 2$$ giving your answer in terms of e.
(ii) Prove, by counter-example, that the statement $$\text { "ln } \left( 3 x ^ { 2 } + 5 x + 3 \right) \geq 0 \text { for all real values of } x \text { " }$$ is false.

2. (i) Solve the equation

$$\ln ( 3 x + 1 ) = 2$$

giving your answer in terms of e.\\
(ii) Prove, by counter-example, that the statement

$$\text { "ln } \left( 3 x ^ { 2 } + 5 x + 3 \right) \geq 0 \text { for all real values of } x \text { " }$$

is false.\\

\hfill \mbox{\textit{OCR C3  Q2 [7]}}