AQA FP1 2014 June — Question 2 11 marks

Exam BoardAQA
ModuleFP1 (Further Pure Mathematics 1)
Year2014
SessionJune
Marks11
PaperDownload PDF ↗
Mark schemeDownload PDF ↗
TopicRoots of polynomials
TypeEquation with nonlinearly transformed roots
DifficultyStandard +0.3 This is a standard FP1 roots of equations question testing Vieta's formulas and symmetric functions. Parts (a) and (b) are routine applications of sum/product formulas and algebraic manipulation. Part (c) requires finding sum and product of transformed roots, which is a textbook technique for this module. While it has multiple steps and requires careful algebra, it follows predictable patterns without requiring novel insight.
Spec4.05a Roots and coefficients: symmetric functions4.05b Transform equations: substitution for new roots

The quadratic equation $$2x^2 + 8x + 1 = 0$$ has roots \(\alpha\) and \(\beta\).
  1. Write down the value of \(\alpha + \beta\) and the value of \(\alpha\beta\). [2 marks]
    1. Find the value of \(\alpha^2 + \beta^2\). [2 marks]
    2. Hence, or otherwise, show that \(\alpha^4 + \beta^4 = \frac{449}{2}\). [2 marks]
  2. Find a quadratic equation, with integer coefficients, which has roots $$2\alpha^4 + \frac{1}{\beta^2} \text{ and } 2\beta^4 + \frac{1}{\alpha^2}$$ [5 marks]

Question 2:
2
Question 2:
2
The quadratic equation
$$2x^2 + 8x + 1 = 0$$
has roots $\alpha$ and $\beta$.

\begin{enumerate}[label=(\alph*)]
\item Write down the value of $\alpha + \beta$ and the value of $\alpha\beta$. [2 marks]

\item 
\begin{enumerate}[label=(\roman*)]
\item Find the value of $\alpha^2 + \beta^2$. [2 marks]

\item Hence, or otherwise, show that $\alpha^4 + \beta^4 = \frac{449}{2}$. [2 marks]
\end{enumerate}

\item Find a quadratic equation, with integer coefficients, which has roots
$$2\alpha^4 + \frac{1}{\beta^2} \text{ and } 2\beta^4 + \frac{1}{\alpha^2}$$
[5 marks]
\end{enumerate}

\hfill \mbox{\textit{AQA FP1 2014 Q2 [11]}}