(i)[1]
Show that $z = 3x + \frac{1200}{x}$
(ii)[6]
Find the stationary value of $z$ and determine what kind of stationary point it is.
Mathematics 9709 · AS & A Level · Differentiation
Differentiation — practice question
The variables $x$, $y$ and $z$ are restricted to positive values, and they satisfy $z = 3x + 2y$ together with $xy = 600$.
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This 7-mark question has a full step-by-step worked solution and mark scheme. One marking point: “A suitable form is $z=3x+\frac{600}{x}$ or an equivalent expression” …
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