Mathematics 9709 · AS & A Level · Integration

Integration — practice question

The diagram depicts the curve $y = f(x)$ for $x > 0$. It has a minimum at $A$ and meets the $x$-axis at $B$ and $C$. You are given that $\frac{dy}{dx} = 2x - \frac{2}{x^3}$ and that the curve goes through the point $\left(4, \frac{189}{16}\right)$.
(i)[2]

Find the $x$-value of $A$.

(ii)[3]

Find the expression for $f(x)$.

(iii)[4]

Find the $x$-values of $B$ and $C$.

(iv)[4]

Find, showing all necessary working, the area enclosed by the shaded region.

Worked solution & mark scheme

This 13-mark question has a full step-by-step worked solution and mark scheme. One marking point: Set the derivative equal to zero: $2x-2/x^3=0$

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