CAIE Further Paper 1 2023 June — Question 2

Exam BoardCAIE
ModuleFurther Paper 1 (Further Paper 1)
Year2023
SessionJune
PaperDownload PDF ↗
Mark schemeDownload PDF ↗
TopicRoots of polynomials

2 The cubic equation \(x ^ { 3 } + 4 x ^ { 2 } + 6 x + 1 = 0\) has roots \(\alpha , \beta , \gamma\).
  1. Find the value of \(\alpha ^ { 2 } + \beta ^ { 2 } + \gamma ^ { 2 }\).
  2. Use standard results from the list of formulae (MF19) to show that $$\sum _ { r = 1 } ^ { n } \left( ( \alpha + r ) ^ { 2 } + ( \beta + r ) ^ { 2 } + ( \gamma + r ) ^ { 2 } \right) = n \left( n ^ { 2 } + a n + b \right)$$ where \(a\) and \(b\) are constants to be determined.

2 The cubic equation $x ^ { 3 } + 4 x ^ { 2 } + 6 x + 1 = 0$ has roots $\alpha , \beta , \gamma$.\\
(a) Find the value of $\alpha ^ { 2 } + \beta ^ { 2 } + \gamma ^ { 2 }$.\\

(b) Use standard results from the list of formulae (MF19) to show that

$$\sum _ { r = 1 } ^ { n } \left( ( \alpha + r ) ^ { 2 } + ( \beta + r ) ^ { 2 } + ( \gamma + r ) ^ { 2 } \right) = n \left( n ^ { 2 } + a n + b \right)$$

where $a$ and $b$ are constants to be determined.\\

\hfill \mbox{\textit{CAIE Further Paper 1 2023 Q2}}