2012 GCE A Level H2 Mathematics Paper 1 Suggested Solutions

冷风1985

如有错误，欢迎指出。

幸运2012

请问你觉得化学题的难度怎么样？

frekiwang

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.

frekiwang

'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.

frekiwang

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.

冷风1985

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. :)