Mathematics 9709 · AS & A Level · Quadratics

Quadratics — practice question

The functions $f$, $g$ and $h$ are given by: $f : x \mapsto x - 4x^{\frac{1}{2}} + 1$ for $x \geq 0$, $g : x \mapsto mx^2 + n$ for $x \geq -2$, where $m$ and $n$ are constants, $h : x \mapsto x^{\frac{1}{2}} - 2$ for $x \geq 0$.
(a)[4]

Solve the equation $f(x) = 0$, expressing your answers in the form $x = a + b\sqrt{c}$, where $a$, $b$ and $c$ are integers.

(b)[4]

Given that $f(x) = gh(x)$, work out the values of $m$ and $n$.

Worked solution & mark scheme

This 8-mark question has a full step-by-step worked solution and mark scheme. One marking point: Obtain the quadratic in $x^{-2}$ and hence find $x^{-2}=2\pm\sqrt{3}$

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