User interface language: English | Español

Date May 2021 Marks available 1 Reference code 21M.1.SL.TZ2.12
Level Standard Level Paper Paper 1 Time zone Time zone 2
Command term Write down Question number 12 Adapted from N/A

Question

Consider the function f(x)=ax2+bx+c. The graph of y=f(x) is shown in the diagram. The vertex of the graph has coordinates (0.5, 12.5). The graph intersects the x-axis at two points, (2, 0) and (p, 0).

Find the value of p.

[1]
a.

Find the value of

(i)     a.

(ii)    b.

(iii)   c.

[5]
b.

Write down the equation of the axis of symmetry of the graph.

[1]
c.

Markscheme

3         A1


Note: Accept (3, 0) seen.


[1 mark]

a.

METHOD 1

0=4a-2b+c,  0=9a+3b+c,  -252=14a+12b+c            (M1)(A1) 

(i)     2         A1

(ii)    -2         A1

(iii)   -12         A1


Note: Award the (M1)(A1) if at least one correct value is seen. Do not apply FT form part (a) if workings are not shown.


METHOD 2

-12.5=a0.5+20.5-3            (M1)

(i)     a=2         A1

        0=2×32+3b+c

        0=2×-22+-2b+c            (M1)

(ii)    b=-2         A1

(iii)   c=-12         A1


[5 marks]

b.

x=0.5          A1


Note: Do not FT from their part (b), this is a contradiction with the diagram.


[1 mark]

c.

Examiners report

[N/A]
a.
[N/A]
b.
[N/A]
c.

Syllabus sections

Topic 2—Functions » SL 2.5—Modelling functions
Show 306 related questions
Topic 2—Functions

View options