OCR Further Pure Core 1 2021 June — Question 1 4 marks

Exam BoardOCR
ModuleFurther Pure Core 1 (Further Pure Core 1)
Year2021
SessionJune
Marks4
TopicRoots of polynomials
TypeQuadratic with transformed roots
DifficultyStandard +0.3 Part (a) is direct application of sum/product of roots formulas. Part (b) requires algebraic manipulation to find the sum and product of transformed roots, which is a standard Further Maths technique but involves more steps than typical A-level questions. The series question is routine application of standard formulae. Overall slightly easier than average for Further Maths content.
Spec4.05a Roots and coefficients: symmetric functions4.06a Summation formulae: sum of r, r^2, r^3

1 In this question you must show detailed reasoning.
The quadratic equation \(x ^ { 2 } - 2 x + 5 = 0\) has roots \(\alpha\) and \(\beta\).
  1. Write down the values of \(\alpha + \beta\) and \(\alpha \beta\).
  2. Hence find a quadratic equation with roots \(\alpha + \frac { 1 } { \beta }\) and \(\beta + \frac { 1 } { \alpha }\). Using the formulae for \(\sum _ { r = 1 } ^ { n } r\) and \(\sum _ { r = 1 } ^ { n } r ^ { 2 }\), show that \(\sum _ { r = 1 } ^ { 10 } r ( 3 r - 2 ) = 1045\).

1 In this question you must show detailed reasoning.\\
The quadratic equation $x ^ { 2 } - 2 x + 5 = 0$ has roots $\alpha$ and $\beta$.
\begin{enumerate}[label=(\alph*)]
\item Write down the values of $\alpha + \beta$ and $\alpha \beta$.
\item Hence find a quadratic equation with roots $\alpha + \frac { 1 } { \beta }$ and $\beta + \frac { 1 } { \alpha }$.

Using the formulae for $\sum _ { r = 1 } ^ { n } r$ and $\sum _ { r = 1 } ^ { n } r ^ { 2 }$, show that $\sum _ { r = 1 } ^ { 10 } r ( 3 r - 2 ) = 1045$.
\end{enumerate}

\hfill \mbox{\textit{OCR Further Pure Core 1 2021 Q1 [4]}}
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