Mathematics 9709 · AS & A Level · Trigonometry

Trigonometry — practice question

The diagram displays a section of the graph of $y = a\cos(bx) + c$.
(a)[3]

Find the three positive integers $a$, $b$ and $c$.

(b(i))[1]

For these values of $a$, $b$ and $c$, use the diagram provided to find how many solutions there are in the interval $0 \leq x \leq 2\pi$ for the equation $a\cos(bx) + c = \frac{6}{\pi}x$.

(b(ii))[1]

For these values of $a$, $b$ and $c$, use the diagram provided to find how many solutions there are in the interval $0 \leq x \leq 2\pi$ for the equation $a\cos(bx) + c = 6 - \frac{6}{\pi}x$.

Worked solution & mark scheme

This 5-mark question has a full step-by-step worked solution and mark scheme. One marking point: $a=5$.

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