| Date | May 2010 | Marks available | 4 | Reference code | 10M.1.sl.TZ1.1 |
| Level | SL only | Paper | 1 | Time zone | TZ1 |
| Command term | Find | Question number | 1 | Adapted from | N/A |
Question
Let f(x)=8x−2x2 . Part of the graph of f is shown below.
Find the x-intercepts of the graph.
[4]
a.
(i) Write down the equation of the axis of symmetry.
(ii) Find the y-coordinate of the vertex.
[3]
b(i) and (ii).
Markscheme
evidence of setting function to zero (M1)
e.g. f(x)=0 , 8x=2x2
evidence of correct working A1
e.g. 0=2x(4−x) , −8±√64−4
x-intercepts are at 4 and 0 (accept (4, 0) and (0, 0) , or x=4 , x=0 ) A1A1 N1N1
[4 marks]
a.
(i) x=2 (must be equation) A1 N1
(ii) substituting x=2 into f(x) (M1)
y=8 A1 N2
[3 marks]
b(i) and (ii).
Examiners report
This question was answered well by most candidates.
a.
This question was answered well by most candidates. Some did not give an equation for their axis of symmetry.
b(i) and (ii).
Syllabus sections
Topic 2 - Functions and equations » 2.4 » The quadratic function x↦ax2+bx+c : its graph, y-intercept (0,c). Axis of symmetry.
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