The function $f$ is given by $f(x) = \frac{1}{3}(2x - 1)^{\frac{3}{2}} - 2x$ for $\frac{1}{2} < x < a$. It is stated that $f$ decreases as $x$ increases.
(main)[4]
Determine the greatest possible value of the constant $a$.
Worked solution & mark scheme
This 4-mark question has a full step-by-step worked solution and mark scheme. One marking point: “Derivative or inverse-method step gives $\sqrt{2x-1}-2$” …