OCR MEI Further Numerical Methods Specimen — Question 3 4 marks

Exam BoardOCR MEI
ModuleFurther Numerical Methods (Further Numerical Methods)
SessionSpecimen
Marks4
PaperDownload PDF ↗
Mark schemeDownload PDF ↗
TopicFixed Point Iteration
TypeApply iteration to find root (pure fixed point)
DifficultyChallenging +1.2 This is a Further Maths numerical methods question requiring understanding of fixed point iteration and relaxation techniques. Part (i) involves computing a few iterations to demonstrate divergence (straightforward calculation), while part (ii) applies a given relaxation formula iteratively until convergence. The concepts are moderately advanced but the execution is computational rather than requiring novel insight—students follow prescribed procedures with a calculator.
Spec1.09c Simple iterative methods: x_{n+1} = g(x_n), cobweb and staircase diagrams1.09d Newton-Raphson method

3 The equation \(\sinh x + x ^ { 2 } - 1 = 0\) has a root, \(\alpha\), such that \(0 < \alpha < 1\).
  1. Verify that the iteration \(x _ { r + 1 } = \frac { 1 - \sinh x _ { r } } { x _ { r } }\) with \(x _ { 0 } = 1\) fails to converge to this root.
  2. Use the relaxed iteration \(x _ { r + 1 } = ( 1 - \lambda ) x _ { r } + \lambda \left( \frac { 1 - \sinh x _ { r } } { x _ { r } } \right)\) with \(\lambda = \frac { 1 } { 4 }\) and \(x _ { 0 } = 1\) to find \(\alpha\) correct to 6 decimal places.

Question 3:
AnswerMarks Guidance
3(i) 1(cid:16)sinh1
soi
1
AnswerMarks
− 0.175.., − 6.7128…, − 61.442… so failsM1
A1
AnswerMarks
[2]1.1
2.2aAt least 3 iterates BC
NAlternative Method α ≈ 1 and
substitution in
(cid:16)xcoshx(cid:16)1(cid:14)sinhx
gʹ(x) =
x2
g'(x) (cid:124)1.368(cid:33)1 so iteration
fails
AnswerMarks Guidance
3(ii) 0.706199, 0.612353, 0.601606, 0.601403, 0.601402,..
0.601402 caoM1
A1
AnswerMarks
[2]1.1
1.1E
Must see at least 3 iterates
AnswerMarks
BCAnswer only does not score
Question 3:
3 | (i) | 1(cid:16)sinh1
soi
1
− 0.175.., − 6.7128…, − 61.442… so fails | M1
A1
[2] | 1.1
2.2a | At least 3 iterates BC
N | Alternative Method α ≈ 1 and
substitution in
(cid:16)xcoshx(cid:16)1(cid:14)sinhx
gʹ(x) =
x2
g'(x) (cid:124)1.368(cid:33)1 so iteration
fails
3 | (ii) | 0.706199, 0.612353, 0.601606, 0.601403, 0.601402,..
0.601402 cao | M1
A1
[2] | 1.1
1.1 | E
Must see at least 3 iterates
BC | Answer only does not score
3 The equation $\sinh x + x ^ { 2 } - 1 = 0$ has a root, $\alpha$, such that $0 < \alpha < 1$.\\
(i) Verify that the iteration $x _ { r + 1 } = \frac { 1 - \sinh x _ { r } } { x _ { r } }$ with $x _ { 0 } = 1$ fails to converge to this root.\\
(ii) Use the relaxed iteration $x _ { r + 1 } = ( 1 - \lambda ) x _ { r } + \lambda \left( \frac { 1 - \sinh x _ { r } } { x _ { r } } \right)$ with $\lambda = \frac { 1 } { 4 }$ and $x _ { 0 } = 1$ to find $\alpha$ correct to 6 decimal places.

\hfill \mbox{\textit{OCR MEI Further Numerical Methods  Q3 [4]}}