Edexcel F1 2021 January — Question 4 8 marks

Exam BoardEdexcel
ModuleF1 (Further Pure Mathematics 1)
Year2021
SessionJanuary
Marks8
PaperDownload PDF ↗
TopicRoots of polynomials
TypeQuadratic with transformed roots
DifficultyStandard +0.8 This is a Further Maths question requiring manipulation of symmetric functions of roots. Part (a) needs the identity α³+β³=(α+β)³-3αβ(α+β) using Vieta's formulas. Part (b) requires finding sum and product of transformed roots α²/β and β²/α, involving algebraic manipulation with α+β and αβ. While systematic, it demands fluency beyond standard A-level and multiple non-trivial algebraic steps.
Spec4.05a Roots and coefficients: symmetric functions4.05b Transform equations: substitution for new roots

  1. The equation \(2 x ^ { 2 } + 5 x + 7 = 0\) has roots \(\alpha\) and \(\beta\)
Without solving the equation
  1. determine the exact value of \(\alpha ^ { 3 } + \beta ^ { 3 }\)
  2. form a quadratic equation, with integer coefficients, which has roots $$\frac { \alpha ^ { 2 } } { \beta } \text { and } \frac { \beta ^ { 2 } } { \alpha }$$ \includegraphics[max width=\textwidth, alt={}, center]{f8660b02-384e-460f-a0e4-282ef5fef475-09_2255_50_314_34}
    VIXV SIHIANI III IM IONOOVIAV SIHI NI JYHAM ION OOVI4V SIHI NI JLIYM ION OO

\begin{enumerate}
  \item The equation $2 x ^ { 2 } + 5 x + 7 = 0$ has roots $\alpha$ and $\beta$
\end{enumerate}

Without solving the equation\\
(a) determine the exact value of $\alpha ^ { 3 } + \beta ^ { 3 }$\\
(b) form a quadratic equation, with integer coefficients, which has roots

$$\frac { \alpha ^ { 2 } } { \beta } \text { and } \frac { \beta ^ { 2 } } { \alpha }$$

\includegraphics[max width=\textwidth, alt={}, center]{f8660b02-384e-460f-a0e4-282ef5fef475-09_2255_50_314_34}\\

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VIXV SIHIANI III IM IONOO & VIAV SIHI NI JYHAM ION OO & VI4V SIHI NI JLIYM ION OO \\
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\hfill \mbox{\textit{Edexcel F1 2021 Q4 [8]}}