CAIE FP1 2012 November — Question 7

Exam BoardCAIE
ModuleFP1 (Further Pure Mathematics 1)
Year2012
SessionNovember
TopicRoots of polynomials

7 A cubic equation has roots \(\alpha , \beta\) and \(\gamma\) such that $$\begin{aligned} \alpha + \beta + \gamma & = 4
\alpha ^ { 2 } + \beta ^ { 2 } + \gamma ^ { 2 } & = 14
\alpha ^ { 3 } + \beta ^ { 3 } + \gamma ^ { 3 } & = 34 \end{aligned}$$ Find the value of \(\alpha \beta + \beta \gamma + \gamma \alpha\). Show that the cubic equation is $$x ^ { 3 } - 4 x ^ { 2 } + x + 6 = 0$$ and solve this equation.