Mathematics 9709 · AS & A Level · Differentiation

Differentiation — practice question

The non-zero variables $x$, $y$, and $u$ satisfy $u = x^2y$. It is given that $y + 3x = 9$.

(main)[7]

Find the stationary value of $u$, then determine whether it is a maximum or a minimum value.

Worked solution & mark scheme

This 7-mark question has a full step-by-step worked solution and mark scheme. One marking point: “Writes $u$ using a single variable” …