Graphs 9
3 marks · NormalThe curve has stationary points.
Find the coordinates of the stationary points and determine whether each is a maximum or a minimum.
Work this out on paper, then compare with the answer and worked solution below. With a free account you can submit written answers for marking.
Show answer
(1, 9): maximum; (3, 5): minimum
Also accept: (1,9) maximum; (3,5) minimum
Common mistakes: Forgetting to find y-coordinate; Incorrect sign for second derivative
Show mark scheme and worked solution
Marking points
M1 · 1 mark · Finds and sets .
A1 · 1 mark · Finds both stationary x-values correctly: 1 and 3.
A2 · 1 mark · Correctly classifies each stationary point (max/min) using second derivative.
Worked solution
When : (point (1,9)). When : (point (3,5)).
At : (negative, so maximum).
At : (positive, so minimum).