WJEC Unit 1 2022 June — Question 12 9 marks

Exam BoardWJEC
ModuleUnit 1 (Unit 1)
Year2022
SessionJune
Marks9
PaperDownload PDF ↗
Mark schemeDownload PDF ↗
TopicFactor & Remainder Theorem
TypeFind factor then solve
DifficultyModerate -0.3 Part (a) requires factorising a cubic (likely by trial of rational roots) then solving a quadratic - standard but multi-step. Part (b) is routine inverse cosine with angle manipulation and range consideration. Both are textbook exercises requiring technique rather than insight, slightly easier than average due to straightforward methods.
Spec1.02j Manipulate polynomials: expanding, factorising, division, factor theorem1.05o Trigonometric equations: solve in given intervals

  1. Solve the equation \(2x^3 - x^2 - 5x - 2 = 0\). [6]
  2. Find all values of \(\theta\) in the range \(0° < \theta < 180°\) satisfying $$\cos(2\theta - 51°) = 0.891.$$ [3]

\begin{enumerate}[label=(\alph*)]
\item Solve the equation $2x^3 - x^2 - 5x - 2 = 0$. [6]
\item Find all values of $\theta$ in the range $0° < \theta < 180°$ satisfying
$$\cos(2\theta - 51°) = 0.891.$$ [3]
\end{enumerate}

\hfill \mbox{\textit{WJEC Unit 1 2022 Q12 [9]}}