OCR MEI Further Numerical Methods Specimen — Question 1 5 marks

Exam BoardOCR MEI
ModuleFurther Numerical Methods (Further Numerical Methods)
SessionSpecimen
Marks5
PaperDownload PDF ↗
Mark schemeDownload PDF ↗
TopicNumerical integration
TypeTrapezium rule applied to real-world data
DifficultyStandard +0.8 This question requires understanding of ill-conditioning and error propagation in linear systems, going beyond routine solving to analyze numerical reliability. While the algebra is straightforward, recognizing that small coefficient changes cause large solution changes requires insight into numerical analysis concepts not typically emphasized in standard A-level content.
Spec1.02c Simultaneous equations: two variables by elimination and substitution

1
  1. Solve the following simultaneous equations. $$\begin{aligned} & x + \quad y = 1 \\ & x + 0.99 y = 2 \end{aligned}$$
  2. The coefficient 0.99 is correct to two decimal places. All other coefficients in the equations are exact. With the aid of suitable calculations, explain why your answer to part (i) is unreliable.

Question 1:
AnswerMarks Guidance
1(i) x = 101
y = −100B1
B1
AnswerMarks
[2]1.1
1.1
AnswerMarks Guidance
1(ii) Substitution of 0.985 and 0.995 to obtain
−200 < y < − 66.67
67.67 < x < 201
E.g. calculation involves subtraction of nearly equal
AnswerMarks
numbersB1
B1
E1
AnswerMarks
[3]1.1
1.1
2.4
AnswerMarks
IN
For either condition
E
For either condition
M
E.g. equations represent lines
which are almost parallel, so a
small change in gradient affects
the point of intersection
AnswerMarks
dramaticallyOr maximum possible error is
100%
Or full argument based on
determinants or gradients
Do not allow general statements
such as “the problem is ill-
conditioned”
Question 1:
1 | (i) | x = 101
y = −100 | B1
B1
[2] | 1.1
1.1
1 | (ii) | Substitution of 0.985 and 0.995 to obtain
−200 < y < − 66.67
67.67 < x < 201
E.g. calculation involves subtraction of nearly equal
numbers | B1
B1
E1
[3] | 1.1
1.1
2.4
I | N
For either condition
E
For either condition
M
E.g. equations represent lines
which are almost parallel, so a
small change in gradient affects
the point of intersection
dramatically | Or maximum possible error is
100%
Or full argument based on
determinants or gradients
Do not allow general statements
such as “the problem is ill-
conditioned”
1 (i) Solve the following simultaneous equations.

$$\begin{aligned}
& x + \quad y = 1 \\
& x + 0.99 y = 2
\end{aligned}$$

(ii) The coefficient 0.99 is correct to two decimal places. All other coefficients in the equations are exact. With the aid of suitable calculations, explain why your answer to part (i) is unreliable.

\hfill \mbox{\textit{OCR MEI Further Numerical Methods  Q1 [5]}}