(i)[3]
Find an expression for $f'(x)$ and use it to justify why $f$ has an inverse.
(ii)[4]
Find an expression for $f^{-1}(x)$, and give the domain and range of $f^{-1}$.
Mathematics 9709 · AS & A Level · Functions
Functions — practice question
The function $f$ is given by $f(x)=\frac{15}{2x+3}$ for $0 \le x \le 6$.
Worked solution & mark scheme
This 7-mark question has a full step-by-step worked solution and mark scheme. One marking point: “Correct derivative $f'(x)=-\frac{30}{(2x+3)^2}$ (the coefficient 2 does not affect the result)” …
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