Edexcel F1 2022 January — Question 6 8 marks

Exam BoardEdexcel
ModuleF1 (Further Pure Mathematics 1)
Year2022
SessionJanuary
Marks8
PaperDownload PDF ↗
TopicRoots of polynomials
TypeSymmetric functions of roots
DifficultyStandard +0.8 This is a Further Maths F1 question requiring manipulation of roots using Vieta's formulas across two related equations. Part (a) is routine recall, but parts (b) and (c) require algebraic manipulation of expressions involving α-3/β and β-3/α, finding their sum and product, then solving for A and B. This demands careful algebraic technique and multi-step reasoning beyond standard A-level, though it's a fairly typical Further Maths roots question.
Spec4.05a Roots and coefficients: symmetric functions

The quadratic equation $$Ax^2 + 5x - 12 = 0$$ where \(A\) is a constant, has roots \(\alpha\) and \(\beta\)
  1. Write down an expression in terms of \(A\) for
    1. \(\alpha + \beta\)
    2. \(\alpha\beta\)
    [2]
The equation $$4x^2 - 5x + B = 0$$ where \(B\) is a constant, has roots \(\alpha - \frac{3}{\beta}\) and \(\beta - \frac{3}{\alpha}\)
  1. Determine the value of \(A\) [3]
  2. Determine the value of \(B\) [3]

The quadratic equation
$$Ax^2 + 5x - 12 = 0$$
where $A$ is a constant, has roots $\alpha$ and $\beta$

\begin{enumerate}[label=(\alph*)]
\item Write down an expression in terms of $A$ for
\begin{enumerate}[label=(\roman*)]
\item $\alpha + \beta$
\item $\alpha\beta$
\end{enumerate}
[2]
\end{enumerate}

The equation
$$4x^2 - 5x + B = 0$$
where $B$ is a constant, has roots $\alpha - \frac{3}{\beta}$ and $\beta - \frac{3}{\alpha}$

\begin{enumerate}[label=(\alph*)]
\setcounter{enumi}{1}
\item Determine the value of $A$
[3]

\item Determine the value of $B$
[3]
\end{enumerate}

\hfill \mbox{\textit{Edexcel F1 2022 Q6 [8]}}