Higher November 2018 Paper 3 Q22
22 An approximate solution to an equation is found using the iterative formula
\(x_{n+1} = \dfrac{(x_n)^3 - 2}{10} \qquad\) with \(\quad x_1 = {-1}\)
(a) Work out the values of \(x_2\) and \(x_3\) [2 marks]
(b) Work out the solution to 5 decimal places. [1 mark]
| Answer | Mark | Comments |
|---|---|---|
| \(-0.3\) or \(-\dfrac{3}{10}\) | B1 | |
| \(-0.2027\) or \(-\dfrac{2027}{10\,000}\) | B1ft | ft their \(-0.3\) |
Additional guidance
ft answer must be to at least 4 decimal places
Note: if their \(-0.3\) is \(-0.2027\), then ft answer is \(-0.200\,832\,8…\)
| Answer | Mark | Comments |
|---|---|---|
| \(-0.20081\) | B1 |
Additional guidance
| Answer must be to exactly 5 decimal places | |
| \(-0.20083\) | B0 |