June 2023 Paper 2 Q1
1 Determine the sum of the infinite geometric series \(9 - 3 + 1 - \frac{1}{3} + \frac{1}{9} + \ldots\) [3]
| Scheme | Marks | AO |
|---|---|---|
| \(\frac{a}{1-r}\) used | M1 | 1.1a |
| \(\dfrac{9}{1 \pm \frac{1}{3}}\) soi | M1 | 1.1 |
| \(\frac{27}{4}\) or \(6\frac{3}{4}\) or 6.75 cao isw | A1 | 1.1 |
| [3] |
Notes
M1: \(a\) and \(r\) are numerical values; \(a = 9\) and/or \(r = \pm\frac{1}{3}\)
A1: if unsupported allow SC2 for correct answer