AQA Further AS Paper 1 2019 June — Question 14

Exam BoardAQA
ModuleFurther AS Paper 1 (Further AS Paper 1)
Year2019
SessionJune
TopicRoots of polynomials

14 The graph of \(y = x ^ { 3 } - 3 x\) is shown below.
\includegraphics[max width=\textwidth, alt={}, center]{948391d8-10ad-44ce-b254-7f1aaac5c82c-22_718_771_370_632} The two stationary points have \(x\)-coordinates of - 1 and 1
The cubic equation $$x ^ { 3 } - 3 x + p = 0$$ where \(p\) is a real constant, has the roots \(\alpha , \beta\) and \(\gamma\).
The roots \(\alpha\) and \(\beta\) are not real.
14
  1. Explain why \(\alpha + \beta = - \gamma\)
    14
  2. Find the set of possible values for the real constant \(p\).
    14
  3. \(\quad \mathrm { f } ( x ) = 0\) is a cubic equation with roots \(\alpha + 1 , \beta + 1\) and \(\gamma + 1\)
    14
    1. Show that the constant term of \(\mathrm { f } ( x )\) is \(p + 2\)
      14
  4. (ii) Write down the \(x\)-coordinates of the stationary points of \(y = \mathrm { f } ( x )\)
    \includegraphics[max width=\textwidth, alt={}, center]{948391d8-10ad-44ce-b254-7f1aaac5c82c-24_2488_1719_219_150} Question number Additional page, if required.
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    Write the question numbers in the left-hand margin.