2012 GCE A Level H2 Mathematics Paper 1 Suggested Solutions
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本帖最后由 冷风1985 于 7-11-2012 20:23 编辑
如有错误,欢迎指出。
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幸运2012 LV4
发表于 7-11-2012 21:50:53
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frekiwang LV15
发表于 9-11-2012 19:32:41
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7(iii) answer is right but method is not acceptable. No calculator is allowed, not even scientific one. Therefore logarithm is not allowed. Students are expected to write down 2^9=512 and 2^10=1024 to make a conclusion.
11(i) theta is restricted in the domain of [0,pi].
when theta->0, dy/dx->+infinity only, tangent 'tends to' (cannot use 'become') a vertical line with a positive gradient.
when theta->pi, dy/dx->-infinity only, tangent tends to a vertical line with a negative gradient. |
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frekiwang LV15
发表于 10-11-2012 07:34:16
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本帖最后由 frekiwang 于 10-11-2012 07:40 编辑
'n>log2 1000 implies nmin=10' evidences the use of at least a scientific calculator without showing the essential working.
The omitting of crucial step such as '2^10=1024' will result in a loss in marks.
Similar idea such as if in answering a question requiring no use of calculator,
sin(0.6)>0.5 is not an acceptable working, but sin(0.6)>sin(pi/6)=0.5 is. |
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frekiwang LV15
发表于 11-11-2012 19:08:40
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本帖最后由 frekiwang 于 11-11-2012 19:20 编辑
log2(1024)=10, is fine, it shows the evidence of not using a calculator.
n>log2(1000)
n_min=10 is not an working that demonstrates that working.
Students need to write 9=log2(512)<log2(1000)<log2(1024)=10 before n_min=10 to support their conclusion is drawn not from a calculator.
When the question restricts the students to use a certain approach, such as Hence (without otherwise), students have to evidence that they are using the required method by showing essential working steps.
Similar example includes:
Without using a calculator
(1+i)^3=-2+2i will result in a loss of marks
Students are expected to write (1+i)^3=1+3i-3-i=-2+2i or more other intermediate steps to demonstrate they are expanding the expression.
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冷风1985 LV8
发表于 11-11-2012 22:23:27
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frekiwang 发表于 11-11-2012 19:08 
log2(1024)=10, is fine, it shows the evidence of not using a calculator.
n>log2(1000)
Thanks for sharing. :)
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