1MA0 Higher November 2012 Paper 1 Q26
26
(a) Rationalise the denominator of \(\dfrac{5}{\sqrt{2}}\) (2)
(b) Expand and simplify \((2 + \sqrt{3})^2 - (2 - \sqrt{3})^2\) (2)
| Answer | Mark | Notes |
|---|---|---|
| \(\dfrac{5\sqrt{2}}{2}\) | 2 | M1 for \(\dfrac{5}{\sqrt{2}} \times \dfrac{\sqrt{2}}{\sqrt{2}}\) oe A1 for \(\dfrac{5\sqrt{2}}{2}\) oe |
| Answer | Mark | Notes |
|---|---|---|
| \(8\sqrt{3}\) | 2 | M1 for \(2 \times 2 + 2\sqrt{3} + 2\sqrt{3} + \sqrt{3} \times \sqrt{3}\) or \((4 + 4\sqrt{3} + 3) - (4 - 4\sqrt{3} + 3)\) or \(2 \times 2 - 2\sqrt{3} - 2\sqrt{3} + \sqrt{3} \times \sqrt{3}\) at least three terms in either correct; could be in a grid. A1 cao OR Difference of two squares M1 for \(\left((2 + \sqrt{3}) - (2 - \sqrt{3})\right)\left((2 + \sqrt{3}) + (2 - \sqrt{3})\right)\) A1 cao |