Edexcel F1 2018 January — Question 5 9 marks

Exam BoardEdexcel
ModuleF1 (Further Pure Mathematics 1)
Year2018
SessionJanuary
Marks9
PaperDownload PDF ↗
TopicComplex Numbers Arithmetic
TypeParameter from modulus condition
DifficultyStandard +0.3 This is a straightforward Further Maths question with two standard parts: (i) solving a complex equation by multiplying through and equating real/imaginary parts, and (ii) using the modulus formula to find a parameter. Both require only routine algebraic manipulation with no novel insight, making it slightly easier than average even for Further Maths.
Spec4.02a Complex numbers: real/imaginary parts, modulus, argument4.02e Arithmetic of complex numbers: add, subtract, multiply, divide4.02f Convert between forms: cartesian and modulus-argument

5. (i) Given that $$\frac { 2 z + 3 } { z + 5 - 2 i } = 1 + i$$ find \(z\), giving your answer in the form \(a + b \mathrm { i }\), where \(a\) and \(b\) are real constants.
(ii) Given that $$w = ( 3 + \lambda \mathrm { i } ) ( 2 + \mathrm { i } )$$ where \(\lambda\) is a real constant, and that $$| w | = 15$$ find the possible values of \(\lambda\).

5. (i) Given that

$$\frac { 2 z + 3 } { z + 5 - 2 i } = 1 + i$$

find $z$, giving your answer in the form $a + b \mathrm { i }$, where $a$ and $b$ are real constants.\\
(ii) Given that

$$w = ( 3 + \lambda \mathrm { i } ) ( 2 + \mathrm { i } )$$

where $\lambda$ is a real constant, and that

$$| w | = 15$$

find the possible values of $\lambda$.\\

\hfill \mbox{\textit{Edexcel F1 2018 Q5 [9]}}