SPS SPS FM Pure 2024 June — Question 7 6 marks

Exam BoardSPS
ModuleSPS FM Pure (SPS FM Pure)
Year2024
SessionJune
Marks6
TopicRoots of polynomials
TypeComplex roots with real coefficients
DifficultyStandard +0.3 This is a straightforward application of the complex conjugate root theorem for polynomials with real coefficients. Students must recognize that if i and 2-i are roots, then -i and 2+i must also be roots, then expand (z-i)(z+i)(z-(2-i))(z-(2+i)) to find coefficients. The algebra is routine with no conceptual challenges beyond the standard theorem.
Spec4.02g Conjugate pairs: real coefficient polynomials4.02i Quadratic equations: with complex roots4.02j Cubic/quartic equations: conjugate pairs and factor theorem

7. In the quartic equation \(z ^ { 4 } + a z ^ { 3 } + b z ^ { 2 } + c z + d = 0\), the coefficients \(a , b , c\) and \(d\) are real. Two of the roots of the equation are i and \(2 - \mathrm { i }\). Find the value of \(a , b , c\) and \(d\).
[0pt]

7.

In the quartic equation $z ^ { 4 } + a z ^ { 3 } + b z ^ { 2 } + c z + d = 0$, the coefficients $a , b , c$ and $d$ are real. Two of the roots of the equation are i and $2 - \mathrm { i }$.

Find the value of $a , b , c$ and $d$.\\[0pt]
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\hfill \mbox{\textit{SPS SPS FM Pure 2024 Q7 [6]}}