| Date | November 2008 | Marks available | 2 | Reference code | 08N.2.sl.TZ0.1 |
| Level | SL only | Paper | 2 | Time zone | TZ0 |
| Command term | Express | Question number | 1 | Adapted from | N/A |
Question
Let \(f(x) = 2{x^2} + 4x - 6\) .
Express \(f(x)\) in the form \(f(x) = 2{(x - h)^2} + k\) .
Write down the equation of the axis of symmetry of the graph of f .
Express \(f(x)\) in the form \(f(x) = 2(x - p)(x - q)\) .
Markscheme
evidence of obtaining the vertex (M1)
e.g. a graph, \(x = - \frac{b}{{2a}}\) , completing the square
\(f(x) = 2{(x + 1)^2} - 8\) A2 N3
[3 marks]
\(x = - 1\) (equation must be seen) A1 N1
[1 mark]
\(f(x) = 2(x - 1)(x + 3)\) A1A1 N2
[2 marks]
Examiners report
Many candidates answered this question with great ease. Still, some found themselves unable to correctly find the vertex algebraically, often mixing the signs of the h and k values. Using the GDC may have been a more fruitful approach. Some candidates did not write the axis of symmetry as an equation.
Many candidates answered this question with great ease. Still, some found themselves unable to correctly find the vertex algebraically, often mixing the signs of the h and k values. Using the GDC may have been a more fruitful approach. Some candidates did not write the axis of symmetry as an equation.
Many candidates answered this question with great ease. Still, some found themselves unable to correctly find the vertex algebraically, often mixing the signs of the h and k values. Using the GDC may have been a more fruitful approach. Some candidates did not write the axis of symmetry as an equation.
