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 \(3{x^2} - 6x + 5\) in the form \(a{(x + b)^2} + c\), where a, b, c \( \in \mathbb{Z}\).
(b) Describe a sequence of transformations that transforms the graph of \(y = {x^2}\) to the graph of \(y = 3{x^2} - 6x + 5\).
Markscheme
(a) attempt at completing the square (M1)
\(3{x^2} - 6x + 5 = 3({x^2} - 2x) + 5 = 3{(x - 1)^2} - 1 + 5\) (A1)
\( = 3{(x - 1)^2} + 2\) A1
\((a = 3,{\text{ }}b = - 1,{\text{ }}c = 2)\)
(b) definition of suitable basic transformations:
\({{\text{T}}_1} = \) stretch in y direction scale factor 3 A1
\({{\text{T}}_2} = \) translation \(\left( {\begin{array}{*{20}{c}}
1 \\
0
\end{array}} \right)\) A1
\({{\text{T}}_3} = \) translation \(\left( {\begin{array}{*{20}{c}}
0 \\
2
\end{array}} \right)\) 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.