Edexcel F1 2016 January — Question 3 11 marks

Exam BoardEdexcel
ModuleF1 (Further Pure Mathematics 1)
Year2016
SessionJanuary
Marks11
PaperDownload PDF ↗
TopicRoots of polynomials
TypeQuadratic with transformed roots
DifficultyStandard +0.8 This is a Further Maths question requiring systematic application of Vieta's formulas and algebraic manipulation to find sums/products of transformed roots. Part (b)(ii) requires forming a new quadratic from complex transformed roots (α³-β and β³-α), which demands careful algebraic work across multiple steps. While the techniques are standard for FM, the length and algebraic complexity elevate it above typical questions.
Spec4.05a Roots and coefficients: symmetric functions

3. The quadratic equation $$x ^ { 2 } - 2 x + 3 = 0$$ has roots \(\alpha\) and \(\beta\).
Without solving the equation,
    1. write down the value of \(( \alpha + \beta )\) and the value of \(\alpha \beta\)
    2. show that \(\alpha ^ { 2 } + \beta ^ { 2 } = - 2\)
    3. find the value of \(\alpha ^ { 3 } + \beta ^ { 3 }\)
    1. show that \(\alpha ^ { 4 } + \beta ^ { 4 } = \left( \alpha ^ { 2 } + \beta ^ { 2 } \right) ^ { 2 } - 2 ( \alpha \beta ) ^ { 2 }\)
    2. find a quadratic equation which has roots $$\text { ( } \alpha ^ { 3 } - \beta \text { ) and ( } \beta ^ { 3 } - \alpha \text { ) }$$ giving your answer in the form \(p x ^ { 2 } + q x + r = 0\) where \(p , q\) and \(r\) are integers.

3. The quadratic equation

$$x ^ { 2 } - 2 x + 3 = 0$$

has roots $\alpha$ and $\beta$.\\
Without solving the equation,
\begin{enumerate}[label=(\alph*)]
\item \begin{enumerate}[label=(\roman*)]
\item write down the value of $( \alpha + \beta )$ and the value of $\alpha \beta$
\item show that $\alpha ^ { 2 } + \beta ^ { 2 } = - 2$
\item find the value of $\alpha ^ { 3 } + \beta ^ { 3 }$
\end{enumerate}\item \begin{enumerate}[label=(\roman*)]
\item show that $\alpha ^ { 4 } + \beta ^ { 4 } = \left( \alpha ^ { 2 } + \beta ^ { 2 } \right) ^ { 2 } - 2 ( \alpha \beta ) ^ { 2 }$
\item find a quadratic equation which has roots

$$\text { ( } \alpha ^ { 3 } - \beta \text { ) and ( } \beta ^ { 3 } - \alpha \text { ) }$$

giving your answer in the form $p x ^ { 2 } + q x + r = 0$ where $p , q$ and $r$ are integers.
\end{enumerate}\end{enumerate}

\hfill \mbox{\textit{Edexcel F1 2016 Q3 [11]}}