how was amath paper 2?
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oh i see.. hahas.. but i simply died out at the binomial question, i used 1 hour plus to do that question and yet i still get the wrong answer
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Originally posted by ViewtyKU990:
oh i see.. hahas.. but i simply died out at the binomial question, i used 1 hour plus to do that question and yet i still get the wrong answer
That does not surprise me. Because the night before, I asked my students to do this question...
And half still got the binomial question wrong. And I dun blame them... coz when I was preparing the model answers for them to estimate their losses... the binomial question took me 15mins to do even thought I knew exactly how it was going to proceed.
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i totally missed out the point whereby they didnt give us a x^1 term for a + bx^2
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still remember i can do all the questions in add maths and e maths paper 1 and 2. Like 4 x 100/100 if everything goes smoothly.
Took a look at last year (2008) add math's paper and holy, the geometry question was HARD. Took me a long time to solve it.
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hmmm i lost a total of 12 marks for a maths now..
e maths a few, but i 4got..
hmm i prefer last year paper, i feel that it is easier. how sad that today's plane geometry didnt kill much D:
tangent secant, midpoint, intersecting chord theorem all didnt come out D:
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Originally posted by Mikethm:
Last year, I had 2 students who reported a score of 86% after checking their answers against answers I provided. They both got A2.
This year's paper is only barely just a teensy bit harder... So 85% is a good guage.
Considering more than a third my students lost 25-30 marks this year... I would hope that 80% is the cut off for A1 but I wouldn't hold my breath.
OMG! So high! just like Emath, if we make just a few careless mistakes, and .....
i wonder if the cut-off points of other subjects like physics, chemistry, combined humanities, POA are this high too.
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some other people cannot do the binomial expansion but i worse... cannot do plane geometry. Why can't I see that the congruent triangles have common sides =.=
My eyes have been playing fatal tricks on me in letter writing, comprehension and now this. Hais... I better not had any careless mistakes in paper 2.
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Originally posted by Mikethm:
I think most of you still dun realise that you lost 2 marks.
I will bet my underwear that most people did d2y/dx2 =0 and think it is sufficient proof that it is a point of inflexion. Unfortunately it is not.Visualise the graph of y = x^4
dy/dx = 4x^3
when dy/dx = 0
4x^3=0
x=0
d2y/dx2 = 12x^2
d2y/dx2 = 12(0)^2
d2y/dx2 = 0
Now look at your mental picture of y = x^4, is the turning point a point of inflexion?
To prove point of inflexion, you need to use the outline method.
Yes, I did that.May I assume I got the full 11 marks?
I lost 14 marks from blank questions, but I am pretty confident of getting 86/100.
In fact I NEED the 86/100 to score 81% overall.
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Originally posted by Mikethm:
That does not surprise me. Because the night before, I asked my students to do this question...
And half still got the binomial question wrong. And I dun blame them... coz when I was preparing the model answers for them to estimate their losses... the binomial question took me 15mins to do even thought I knew exactly how it was going to proceed.
Sorry but may I ask you something? I wanted a professional's advice on this.Considering that most of the 'top students' from 'top schools' like ACS(I), RI etc. are in the IB programme, shouldn't the bell curve be less harsh than >85% for an A1?
I understand if pure sciences require more than 85% for an A1, but for mathematics I always thought 80% for an A1 was more than enough.
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Originally posted by Dejomel:
Sorry but may I ask you something? I wanted a professional's advice on this.
Considering that most of the 'top students' from 'top schools' like ACS(I), RI etc. are in the IB programme, shouldn't the bell curve be less harsh than >85% for an A1?
I understand if pure sciences require more than 85% for an A1, but for mathematics I always thought 80% for an A1 was more than enough.
1st, I am not a professional. My interest in the score required was because got one year I got too many B3s.
There are still schools like SCGS, Victoria, Cedar, SJI (1/2 IB, 1/2 O), CHIJ St Nicholas etc etc you know? These schools have 80-90++% distinction ( defined as A1/A2) rates...
On the other hand, my students may have overestimated their scores? But I don't think that is likely as this year's 9 out of 11 students report losses of <33 marks (aka 82%). My average distinction rate is 70-80%. So what they feedback to me make sense as if we assume A2 is around 80%, I will get 82% distinctions.
And if A2 is 80%, A1 should be around 85% no?
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Can post the binomial question here to see how difficult is it ?
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5i) Write down the first three terms in the expansion, in ascending powers of x, of
(2 - x/4)^n , where n is a positive integer greater than 2. (3m)
The first two terms in the expansion, in ascending powers of x, of (1 + x)(2 - x/4)^n are
a + bx^2 , where a and b are constants.
ii) Find the value of n. (3m)
iii) Hence find the value of a and of b. (3m)
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Originally posted by qdtimes2:
5i) Write down the first three terms in the expansion, in ascending powers of x, of
(2 - x/4)^n , where n is a positive integer greater than 2. (3m)
The first two terms in the expansion, in ascending powers of x, of (1 + x)(2 - x/4)^n are
a + bx^2 , where a and b are constants.
ii) Find the value of n. (3m)
iii) Hence find the value of a and of b. (3m)
You might have probably forgotten to type "The first two-non-zero terms are a + bx^2".
The trick to this question is to expand (1 + x)(2 - x/4)^n as usual and equate the x term to 0x as the first two non-zero terms are a + bx^2.
In fact the expansion should be a + 0x + bx^2 but the question is tricky and the question only says the first two non-zero terms are a + bx^2.
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VS prelim came out something similar.
just equate the coefficient of X to 0.and alot of people do not know how to expand nCr.
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Originally posted by Mikethm:
Last year, I had 2 students who reported a score of 86% after checking their answers against answers I provided. They both got A2.
This year's paper is only barely just a teensy bit harder... So 85% is a good guage.
Considering more than a third my students lost 25-30 marks this year... I would hope that 80% is the cut off for A1 but I wouldn't hold my breath.
okay. i hope that its around 83-85%. =(
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Originally posted by qdtimes2:
- the paper has one of the hardest binomial expansion qn i've ever seen
- the qn about differentiation, integration, maxima and minima dropped like a bomb with 11 marks.
conclusion - hard!
Can also post the question about the differentiation, integration, maxima and minima here ?
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Originally posted by qdtimes2:
- the paper has one of the hardest binomial expansion qn i've ever seen
- the qn about differentiation, integration, maxima and minima dropped like a bomb with 11 marks.
conclusion - hard!
Can also post the question about the differentiation, integration, maxima and minima here ?
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no lah, the question didn't state 'non-zero' and i think it's already assumed by many students...
10. A curve is such that d^2y/dx^2 = 6x - 6. The curve passes through the point (3, 10) and at this point the gradient of the curve is 12. Find the coordinates of the stationary point of the curve and determine the nature of this stationary point. (11m)
pretty unique!
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hey honestly, everything was easy except for plane geometry, and the circle find coordinate B... i can do but i go put y = 1/3 x instead of x=3y .. haiz... but i think still can get A1 ba... anyway NO MORE MATHS!!! HUAT AR!
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Originally posted by qdtimes2:
no lah, the question didn't state 'non-zero' and i think it's already assumed by many students...
10. A curve is such that d^2y/dx^2 = 6x - 6. The curve passes through the point (3, 10) and at this point the gradient of the curve is 12. Find the coordinates of the stationary point of the curve and determine the nature of this stationary point. (11m)
pretty unique!
Yes, it is pretty unique.
The question requires the integration of d^2y/dx^2 = 6x - 6, subst dy/dx = 12 and x=3 to get the constant so as to get dy/dx = 3x^2 - 6x + 3. Next, set dy/dx = 0 for stationary point to get x = 1.
Subst x = 1 into d^2y/dx^2 get the answer 0. So, need to subst x = 0.99 , 1, 1.01 into dy/dx to check for the signs ie +, 0, + and hence the stationary point is a point of inflexion.
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Originally posted by qdtimes2:
no lah, the question didn't state 'non-zero' and i think it's already assumed by many students...
10. A curve is such that d^2y/dx^2 = 6x - 6. The curve passes through the point (3, 10) and at this point the gradient of the curve is 12. Find the coordinates of the stationary point of the curve and determine the nature of this stationary point. (11m)
pretty unique!
Can also post the questions on plane geometry and the circle find co-ordinate B ?
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i try lol, i dunno how to upload lolz @_@
4 http://i181.photobucket.com/albums/x78/qdtimes2/2009OlvlPlaneGeometry.jpg
The diagrams shows an isoceles triangle ABC in which AC = BC. Lines are drawn drom A and B to meet BC and AC at P and Q respectively. The lines AP and BQ intersect at X. Give that PC = QC, show that
i) AXB is an isoceles triangle. (5m)
ii) PX = QX (3m)
9 http://i181.photobucket.com/albums/x78/qdtimes2/2009OlvlCircles.jpg
The diagram shows a circle with centre C(2, -1) and radius 5.
i) Given that the equation of the circle is x^2 + y^2 + 2gx + 2fy + c = 0, find the value of each of the constants g, f and c. (3m)
The points A and B lie on the circle such that the line AC is parallel to the x-axis and the line AB passes through the origin O.
ii) Write down the coordinates of A. (1m)
iii) Find the equation of AB. (2m)
iv) Find the coordinates of B. (4m)