Edexcel FP2 2002 June — Question 9 7 marks

Exam BoardEdexcel
ModuleFP2 (Further Pure Mathematics 2)
Year2002
SessionJune
Marks7
PaperDownload PDF ↗
Mark schemeDownload PDF ↗
TopicComplex Numbers Argand & Loci
TypeComplex transformations and mappings
DifficultyStandard +0.3 This is a straightforward Further Maths question with standard techniques: part (a) requires routine manipulation of modulus equations to find a circle of Apollonius (a standard FP2 exercise), and part (b) involves composing two simple transformations by direct substitution. Both parts are textbook-standard with no novel insight required, making it slightly easier than average even for Further Maths.
Spec4.02a Complex numbers: real/imaginary parts, modulus, argument4.02k Argand diagrams: geometric interpretation4.02o Loci in Argand diagram: circles, half-lines

9. (a) The point \(P\) represents a complex number \(z\) in an Argand diagram. Given that $$| z - 2 i | = 2 | z + i |$$
  1. find a cartesian equation for the locus of \(P\), simplifying your answer.
  2. sketch the locus of \(P\).
    (b) A transformation \(T\) from the \(z\)-plane to the \(w\)-plane is a translation \(- 7 + 11\) i followed by an enlargement with centre the origin and scale factor 3 . Write down the transformation \(T\) in the form $$w = a z + b , \quad a , b \in \mathbb { C }$$

Question 9:
Part (a)(i)
AnswerMarks Guidance
AnswerMarks Guidance
\(x+(y-2)i =2
\(\therefore x^2+(y-2)^2=4(x^2+(y+1)^2)\)
Part (a)(ii)
AnswerMarks Guidance
AnswerMarks Guidance
\(3x^2+3y^2+12y=0\) (any correct form; 3 terms)A1 (2)
Sketch circleB1
Centre \((0,-2)\)B1
\(r=2\) or touches axisB1 (3)
Part (b)
AnswerMarks Guidance
AnswerMarks Guidance
\(w=3(z-7+11i)\)B1
\(=3z-21+33i\)B1 (2)
(7 marks)
# Question 9:

## Part (a)(i)
| Answer | Marks | Guidance |
|--------|-------|----------|
| $|x+(y-2)i|=2|x+(y+i)|$ | M1 | |
| $\therefore x^2+(y-2)^2=4(x^2+(y+1)^2)$ | | |

## Part (a)(ii)
| Answer | Marks | Guidance |
|--------|-------|----------|
| $3x^2+3y^2+12y=0$ (any correct form; 3 terms) | A1 | **(2)** |
| Sketch circle | B1 | |
| Centre $(0,-2)$ | B1 | |
| $r=2$ or touches axis | B1 | **(3)** |

## Part (b)
| Answer | Marks | Guidance |
|--------|-------|----------|
| $w=3(z-7+11i)$ | B1 | |
| $=3z-21+33i$ | B1 | **(2)** |
| | | **(7 marks)** |

---
9. (a) The point $P$ represents a complex number $z$ in an Argand diagram. Given that

$$| z - 2 i | = 2 | z + i |$$
\begin{enumerate}[label=(\roman*)]
\item find a cartesian equation for the locus of $P$, simplifying your answer.
\item sketch the locus of $P$.\\
(b) A transformation $T$ from the $z$-plane to the $w$-plane is a translation $- 7 + 11$ i followed by an enlargement with centre the origin and scale factor 3 .

Write down the transformation $T$ in the form

$$w = a z + b , \quad a , b \in \mathbb { C }$$
\end{enumerate}

\hfill \mbox{\textit{Edexcel FP2 2002 Q9 [7]}}