(i)[2]
Find the values of $a$ and $b$ from the information given.
(ii)[1]
Find the range of $f$ from the given information.
(iii)[2]
Find the exact value of $f(\frac{5}{6}\pi)$ from the expression for $f$.
Mathematics 9709 · AS & A Level · Trigonometry
Trigonometry — practice question
The function $f : x \mapsto a + b\cos x$ is defined for $0 \leq x \leq 2\pi$. It is given that $f(0) = 10$ and that $f(\frac{2}{3}\pi) = 1$.
Worked solution & mark scheme
This 5-mark question has a full step-by-step worked solution and mark scheme. One marking point: “Uses $f(0)=10$ or $f(\tfrac{2\pi}{3})=1$ to set up an equation.” …
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