Edexcel CP AS 2023 June — Question 10

Exam BoardEdexcel
ModuleCP AS (Core Pure AS)
Year2023
SessionJune
TopicRoots of polynomials

  1. In this question you must show all stages of your working.
Solutions relying on calculator technology are not acceptable.
  1. The quartic equation $$z ^ { 4 } + 5 z ^ { 2 } - 30 = 0$$ has roots \(p , q , r\) and \(s\).
    Without solving the equation, determine the quartic equation whose roots are $$( 3 p - 1 ) , ( 3 q - 1 ) , ( 3 r - 1 ) \text { and } ( 3 s - 1 )$$ Give your answer in the form \(w ^ { 4 } + a w ^ { 3 } + b w ^ { 2 } + c w + d = 0\), where \(a , b , c\) and \(d\) are integers to be found.
  2. The roots of the cubic equation $$4 x ^ { 3 } + n x + 81 = 0 \quad \text { where } n \text { is a real constant }$$ are \(\alpha , 2 \alpha\) and \(\alpha - \beta\)
    Determine
    (a) the values of the roots of the equation,
    (b) the value of \(n\).