Edexcel F1 2015 June — Question 1 5 marks

Exam BoardEdexcel
ModuleF1 (Further Pure Mathematics 1)
Year2015
SessionJune
Marks5
PaperDownload PDF ↗
TopicFactor & Remainder Theorem
TypePolynomial identity or expansion
DifficultyModerate -0.8 This is a straightforward Further Maths question requiring algebraic expansion to find coefficients, then solving a quadratic (which happens to have complex roots). The factorization is given, making part (a) routine coefficient matching, and part (b) is standard quadratic formula application. Below average difficulty even for Further Maths F1.
Spec4.02g Conjugate pairs: real coefficient polynomials4.02i Quadratic equations: with complex roots

  1. Given that
$$2 z ^ { 3 } - 5 z ^ { 2 } + 7 z - 6 \equiv ( 2 z - 3 ) \left( z ^ { 2 } + a z + b \right)$$ where \(a\) and \(b\) are real constants,
  1. find the value of \(a\) and the value of \(b\).
  2. Given that \(z\) is a complex number, find the three exact roots of the equation $$2 z ^ { 3 } - 5 z ^ { 2 } + 7 z - 6 = 0$$

\begin{enumerate}
  \item Given that
\end{enumerate}

$$2 z ^ { 3 } - 5 z ^ { 2 } + 7 z - 6 \equiv ( 2 z - 3 ) \left( z ^ { 2 } + a z + b \right)$$

where $a$ and $b$ are real constants,\\
(a) find the value of $a$ and the value of $b$.\\
(b) Given that $z$ is a complex number, find the three exact roots of the equation

$$2 z ^ { 3 } - 5 z ^ { 2 } + 7 z - 6 = 0$$

\hfill \mbox{\textit{Edexcel F1 2015 Q1 [5]}}