CAIE Further Paper 1 2023 November — Question 4

Exam BoardCAIE
ModuleFurther Paper 1 (Further Paper 1)
Year2023
SessionNovember
TopicRoots of polynomials

4 The cubic equation \(27 x ^ { 3 } + 18 x ^ { 2 } + 6 x - 1 = 0\) has roots \(\alpha , \beta , \gamma\).
  1. Show that a cubic equation with roots \(3 \alpha + 1,3 \beta + 1,3 \gamma + 1\) is $$y ^ { 3 } - y ^ { 2 } + y - 2 = 0$$ The sum \(( 3 \alpha + 1 ) ^ { n } + ( 3 \beta + 1 ) ^ { n } + ( 3 \gamma + 1 ) ^ { n }\) is denoted by \(\mathrm { S } _ { \mathrm { n } }\).
  2. Find the values of \(S _ { 2 }\) and \(S _ { 3 }\).
  3. Find the values of \(S _ { - 1 }\) and \(S _ { - 2 }\).