Edexcel FP2 — Question 3 7 marks

Exam BoardEdexcel
ModuleFP2 (Further Pure Mathematics 2)
Marks7
PaperDownload PDF ↗
Mark schemeDownload PDF ↗
TopicTaylor series
TypeMaclaurin series for ln(a+bx)
DifficultyStandard +0.3 This is a straightforward application of standard Maclaurin series technique for Further Maths students. Part (a) requires routine differentiation of ln(1+5x) three times using the chain rule, and part (b) applies the standard Maclaurin formula with derivatives evaluated at x=0. While it's a Further Maths topic, it follows a completely standard procedure with no problem-solving or insight required, making it slightly easier than average overall.
Spec1.07l Derivative of ln(x): and related functions4.08a Maclaurin series: find series for function4.08b Standard Maclaurin series: e^x, sin, cos, ln(1+x), (1+x)^n

3. (a) Given that \(y = \ln ( 1 + 5 x ) , | x | < 0.2\), find \(\frac { \mathrm { d } ^ { 3 } y } { \mathrm {~d} x ^ { 3 } }\).
(b) Hence obtain the M aclaurin series for \(\ln ( 1 + 5 x ) , | x | < 0.2\), up to and including the term in \(x ^ { 3 }\).

Question 3:
Part (a):
AnswerMarks Guidance
WorkingMarks Notes
\(\frac{dy}{dx} = \frac{5}{1+5x}\)M1 A1
\(\frac{d^2y}{dx^2} = -\frac{25}{(1+5x)^2}\)A1
\(\frac{d^3y}{dx^3} = \frac{250}{(1+5x)^3}\)A1 (4)
Part (b):
AnswerMarks Guidance
WorkingMarks Notes
\(\ln(1+5x) = 5x - \frac{25}{2}x^2 + \frac{125}{3}x^3 + \ldots\)M1 A1 A1 (3)
# Question 3:

## Part (a):
| Working | Marks | Notes |
|---------|-------|-------|
| $\frac{dy}{dx} = \frac{5}{1+5x}$ | M1 A1 | |
| $\frac{d^2y}{dx^2} = -\frac{25}{(1+5x)^2}$ | A1 | |
| $\frac{d^3y}{dx^3} = \frac{250}{(1+5x)^3}$ | A1 (4) | |

## Part (b):
| Working | Marks | Notes |
|---------|-------|-------|
| $\ln(1+5x) = 5x - \frac{25}{2}x^2 + \frac{125}{3}x^3 + \ldots$ | M1 A1 A1 (3) | |

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3. (a) Given that $y = \ln ( 1 + 5 x ) , | x | < 0.2$, find $\frac { \mathrm { d } ^ { 3 } y } { \mathrm {~d} x ^ { 3 } }$.\\
(b) Hence obtain the M aclaurin series for $\ln ( 1 + 5 x ) , | x | < 0.2$, up to and including the term in $x ^ { 3 }$.\\

\hfill \mbox{\textit{Edexcel FP2  Q3 [7]}}