Mathematics 9709 · AS & A Level · Functions

Functions — practice question

The functions $f$ and $g$ are given by $f(x)=\sqrt{x}$ for $x\geq 0$, and $g(x)=3\sqrt{x+2}-5$ for $x\geq -2$.
(a)[5]

Describe the complete sequence of transformations that carries the graph of $y=f(x)$ to the graph of $y=g(x)$. Make the order in which they are applied clear.

(b)[2]

On the diagram sketch the graph of $y=g^{-1}(x)$ and any relevant mirror line.

(c)[2]

Find a formula for $g^{-1}(x)$.

(d)[1]

State the range for $g^{-1}$.

(e)[1]

The function $h$ is defined for $x \geq 0$ by $h(x) = x - 2$. Find the value of $g^{-1}h(4)$.

(f)[1]

Explain why the composite function $hg^{-1}$ is impossible to define.

Worked solution & mark scheme

This 12-mark question has a full step-by-step worked solution and mark scheme. One marking point: State a stretch by factor $3$ parallel to the $y$‑axis.

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