Mathematics 9709 · AS & A Level · Series

Series — practice question

The function $f$ is defined by $f(x) = x^3 - 3x^2 - 9x + 2$ for $x > n$, where $n$ is an integer. It is stated that $f$ is an increasing function.

(main)[4]

Determine the least possible value of $n$.

Worked solution & mark scheme

This 4-mark question has a full step-by-step worked solution and mark scheme. One marking point: “Correct differentiation gives $f'(x)=3x^2-6x-9$” …