1MA0 Higher June 2012 Paper 2 Q19
19
\[p^2 = \frac{x - y}{xy}\]\(x = 8.5 \times 10^9\)
\(y = 4 \times 10^8\)
Find the value of \(p\).
Give your answer in standard form correct to 2 significant figures. (3)
| Working | Answer | Mark | Notes |
|---|---|---|---|
| \(\sqrt{\dfrac{8.5 \times 10^9 - 4 \times 10^8}{8.5 \times 10^9 \times 4 \times 10^8}}\) \(= \sqrt{\dfrac{8.1 \times 10^9}{3.4 \times 10^{18}}}\) \(= \sqrt{2.3823529\ldots \times 10^{-9}}\) OR \(\sqrt{\dfrac{1}{4 \times 10^8} - \dfrac{1}{8.5 \times 10^9}}\) \(= \sqrt{2.5 \times 10^{-9} - 1.17647 \times 10^{-10}}\) \(= \sqrt{2.3823529\ldots \times 10^{-9}}\) | \(4.9 \times 10^{-5}\) | 3 | B3 for \(4.88 \times 10^{-5}\) to \(4.9 \times 10^{-5}\) (B2 for digits 238(23529) or 24 or 488(09353) or 49) (B1 for digits 81 or 34) OR B3 for \(4.88 \times 10^{-5}\) to \(4.9 \times 10^{-5}\) (B2 for digits 238(23529) or 24 or 488(09353) or 49) (B1 for digits 25 or 117(647)) |