Date | May 2010 | Marks available | 6 | Reference code | 10M.1.hl.TZ2.2 |
Level | HL only | Paper | 1 | Time zone | TZ2 |
Command term | Describe | Question number | 2 | Adapted from | N/A |
Question
(a) Express the quadratic 3x2−6x+5 in the form a(x+b)2+c, where a, b, c ∈Z.
(b) Describe a sequence of transformations that transforms the graph of y=x2 to the graph of y=3x2−6x+5.
Markscheme
(a) attempt at completing the square (M1)
3x2−6x+5=3(x2−2x)+5=3(x−1)2−1+5 (A1)
=3(x−1)2+2 A1
(a=3, b=−1, c=2)
(b) definition of suitable basic transformations:
T1= stretch in y direction scale factor 3 A1
T2= translation (10) A1
T3= translation (02) A1
[6 marks]
Examiners report
There were fewer correct solutions to this question than might be expected with a significant minority of candidates unable to complete the square successfully and a number of candidates unable to describe the transformations. A minority of candidates knew the correct terminology for the transformations and this potentially highlights the need for teachers to teach students appropriate terminology.