Moderate -0.8 This is a straightforward function transformation question requiring students to identify vertical stretch/translation and horizontal translation from a diagram. It involves pattern recognition of standard cosine transformations with no problem-solving or proof required—simpler than average A-level questions.
4
\includegraphics[max width=\textwidth, alt={}, center]{fdd6e942-b5bc-4369-8587-6de120459776-05_615_1169_260_488}
In the diagram, the lower curve has equation \(y = \cos \theta\). The upper curve shows the result of applying a combination of transformations to \(y = \cos \theta\).
Find, in terms of a cosine function, the equation of the upper curve.
4\\
\includegraphics[max width=\textwidth, alt={}, center]{fdd6e942-b5bc-4369-8587-6de120459776-05_615_1169_260_488}
In the diagram, the lower curve has equation $y = \cos \theta$. The upper curve shows the result of applying a combination of transformations to $y = \cos \theta$.
Find, in terms of a cosine function, the equation of the upper curve.\\
\hfill \mbox{\textit{CAIE P1 2020 Q4 [3]}}