Mathematics 9709 · AS & A Level · Trigonometry

Trigonometry — practice question

The polynomial $p(x)$ is given by $p(x) = ax^4 + bx^3 + 13x^2 - 35x + 15$, where $a$ and $b$ are constants. It is stated that $(2x - 1)$ and $(x - 3)$ are factors of $p(x)$.
(a)[4]

Find the values of $a$ and $b$ from this information.

(b)[3]

Hence factorise $p(x)$ completely.

(c)[2]

Find the least positive value of $\theta$ in radians for which $p(\cot 2\theta) = 0$.

Worked solution & mark scheme

This 9-mark question has a full step-by-step worked solution and mark scheme. One marking point: Substitute $x=\tfrac12$ and $x=3$, then set each result equal to zero

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