To the 1.0 × 10^{n} (2 sig. fig.) missed calls & emails (from these few days) that are currently residing in Miss Lo’s handphone now:

~~As Miss Loi is deeply embroiled in her Mega Jφss Sticks sessions during this period of consecutive O Level A/E-Maths papers~~ Please SMS or email your contact number if you’re interested in joining her maths classes for the new season, and she’ll get back to you when things have calmed down in early November – **which starts this week!**

Miss Loi is currently busy with her phone marathon to respond to all on new enquiries and those on the calling list. Will respond to the comments here in due time.

Thank You for your understanding and apologies for the slow response.

Meanwhile, do checkout the Jφss Sticks Facebook wall for the relentless updates 😉

*Loud droning noise overhead*

Another big package just got air-dropped from Jφss Sticks Airways Flight JS296!

Click the button (if you haven’t yet done so) and grab it here!

Latest version:

- 1.1: To stem the horde of AMaths students who go “Miss Loi! Your gradient for Q9(d) is waaaaaaaaay off! My dy/dx says 3.2!”, the tangent has been ‘
*keeeeeewed*‘ (bent) to a gradient of 3.2 to prevent any widespread panic. But seriously, read this.

As usual, please leave a comment should you spot any mistake in the solution – like yesterday, Miss Loi still had students ~~to save~~ at The Temple throughout this evening (including *some* who refused to leave)! tsk tsk

Now to turn the attention to The Temple’s crack elite AMaths Regiment over the weekend … *cracks whip!*

Meanwhile follow the Jφss Sticks Facebook wall to receive The Temple’s **last-minute O Level air-drops cum tips**. It’s all happening there!

**Marching On! Maaarching ON!!!**

## 51 Comments

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Thanks for the answers!

The gradient in 9(d) which I got was way off = 3.05

(dy/dx <x=4, it would be 3.2).

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@Hi: But what if I chose to use A-math too? I tried a lot of times to find the gradient which is 3.2, and I found 3.19...

I even used A-math to find the min point so it looks so accurate... ;(

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@Lala: While it's perfectly fine to use pagan AMaths techniques to double-check your answer, it's not really advisable to write stuff like dy/dx in your final workings.

Though Miss Loi isn't 100% sure of Cambridge's stand on this, why expose yourself to the possible risk of losing method marks for this?

*copy-and-pasted from Miss Loi's email response to someone who asked if it's possible to use Physics

v=u+atformula in AMaths kinematics*曜

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@Hi: 3.05 isn't really considered "way off" IMHO.

In any case, as mentioned in the past years,

"... the gradients of these hand-drawn tangents will tend to vary a little among those who draw them, notwithstanding the lot of A-Maths students who adjust here adjust there till they fit their sneaky dy/dx calculations.

As long as you've demonstrated that you've obtained the gradient (within a tolerable range) at the point via calculating the gradient of

yoursuitably-drawn tangent based on selected coordinates fromyourplot (and make sure you hide away all your sneaky dy/dx workings in the process), you'd be fine ;)"曜

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Question 4 ~

Didn't get part one and part two. (Cannot get (b) equation)

So, will they be marks for part three and four?

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@Luchia Kiryu: Assuming you know the part (d)'s height =

x+ 1, and since Q4(c) & (d) do not rely on any result from parts (a) & (b), you should be fine 😀 *pat pat*曜

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@Miss Loi: Pheeeeew ~ Thanks soo much 😀

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Can the gradient of the graph be 4? Mine turn out to be four..

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@Jolindaz: See above.

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Hi!

Its a year and a half since i last visited your 'virtual temple' at june last year.

Missed the "joss sticks" that you'd given in your posts

Anyway, now i'm back, i realised a few improvements made on your 'temple', like that facebook connect button 😛

reading through your provided answers for this paper, i realised that your gradient is waaaaaaaaaay off. Shouldn't it be around 3.2, for dy/dx=(0.6x16)-(1.6x4)?

and i'm sharing the answers i'd created on this page too:http://noobnaik.files.wordpress.com/2011/10/2011-mathematics-4016-02-answer-scheme.docx

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@Lee Kian Boon: Oh dear it was sooooo waaaaaaaaaaaaaay off! As such, Miss Loi has uploaded v1.1 of the solutions after hiring an AMaths-capable robot to redraw the tangent to a gradient of 3.2 ± 1 × 10

^{−12}using the latest Japanese technology capable of up topicoprecision 😀Wah you're so free to do your own answers, instead of studying for your AMaths, Science etc? You suddenly remind Miss Loi of someone though ... hmmmmmmmmm ...

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Hi ms loi!:) for qn1d, the ans is (2x-y)/x... is it ok if i put 2 - (y/x)? 🙂 thx...

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@vic: No problemo.

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omg , nearest cent = 2dp ? why is it so ?

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@surian: Umm ... 1 cent = $0.01 not $0.10 (at least that's what Miss Loi saw at her local money changer :P)

So should you write $16.20 or $16.2 (weird) instead of $16.24 in Q2(a)(ii)(b) for instance, this would effectively make it "to the nearest 10-cent".

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For qn no 10 why is the x=multiple of 5? shouldnt the number used be 4.5,14.5,24.5 ....etc. There are 10 numbers being: 0,1,2,3,4,5,6,7,8,9 . shouldnt it be the centre terms added then divide by 2? (4+5)/2=4.5?

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@MathA1: The mid-values are simply the physical middle point of each class interval in the histogram.

If we employ the way we use to find the median to obtain 4.5, 14.5 ... etc then these mid-points will no longer be at the center of each bar in the given histogram, unless there are gaps between the bars which don't exist in the given diagram.

P.S. Actually a histogram represents a

frequency distributionso there can never, ever be gaps between bars (else it would be just a bar chart). You may consider the purpose of the ≤ and < signs in the data ranges is to determine which frequency bar the data belongs to.曜

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10(aiia) Shouldn't the middle points be 4.5, 14.5, 24.5 etc?

Because the given parameters are 0 ≤ x < 10, so the possibilities should be 0, 1, 2, 3, 4, 5, 6, 7, 8, 9.

So shouldn't the median be 4.5 to be used in calculation?

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@arvind 🙂: The mid-value of a class interval has got nothing to do with being the median of a data set.

See above.

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Hi， Ms Loi. There are a few qns I'd like to ask for this paper. (actually, is a lot !!! ><' )

1. For Qn 5b(i), is it possible if we say that because p is multiplied by 2 and that makes it an even number, so the addition of 1 made it an odd no. ?

2. For Qn 6a(iv), a friend of mine said that bearings should be rounded off to 3s.f. ...

3. For Qn 7a. if we did not use the proportion method (meaning make an eqn like how you did), would they deduct marks ?

4. For Qn 8,

a,

ii. they would give method marks even if we do not get the answer right ?

b,

i&ii. if we did not put the wave under the letters, would they deduct marks ?

iii. can we say that line OX & OY are parallel, since they are collinear ?

Thanks a thousand !! 😀

and for the answers too ! ^^

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@passer-by: Finally some time to continue replying the comments here *rubs eyes*

Q5(b)(i): You definition should be fine for this 1-mark part. Miss Loi left it this way as the primary definition of an odd number is an integer that is not wholly divisible by 2.

Q6(a)(iv): Umm ... bearings should always contain 3 digits, and since they are in

degrees, they should be rounded off to one decimal place for non-exact answers (as stated in the instructions)Q7(a): You used ratios? i.e. If so, they're basically similar so should be fine 😀

Q8(a)(ii): Method marks are not a myth! More apparently so in a 2-mark question!

Q8(b)(i)(ii): Unfortunately yes. Hence this tip. Unless you somehow managed to

boldthe vector letters to a point that it became obvious (without causing a hole in the paper :P) - but that's quite a waste of time.Q8(b)(iii): All collinear vectors are parallel (but not all parallel vectors are collinear!) so you should be OK - though a paranoid Miss Loi feels that since the question asks for two facts about the

pointsO,XandY, your facts should at least mention directly some of thepointsrather than base them purely on lines or vectors e.g.Xis the mid-point ofOY.曜

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For 7(b)(ii), the surface area of the pot should not include the surface area of the circle because it is an open pot.

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@Rachel: The pot has a base. its top is open but its base has a radius of 24 cm (not 36 cm). The qn clearly states that the base end of the pot has a radius of 24cm.

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@Rachel: As quoted from the Jφss Sticks Facebook wall:

So the pot is only open at the top. If its base is taken away as well, then it's not really a pot anymore isn't it? More like something we use to bake cookies 😛

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hi was wondering why the bearing we were asked to find could be left in 4sf? since bearing is always only 3 numbers?

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@Peace: As mentioned earlier, bearings should always contain 3 digits, and if they are non-exact, should be rounded off to one decimal place since they are in degrees (as stated in the instructions).

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how many marks would be deducted if the significant figure is wrong??

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@mini: −1 max. There are some who say half-marks are possible but so far sample Cambridge mark schemes don't seem to suggest so.

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Miss loi, will I get two mark if I plot the graph wrongly? My P value is correct but I accidentally plot the point (-2,4.8) . The other four point I plotted correctly. And my gradient is 2.8. Does that mean my gradient is wrong?

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@Anonymous: Looking at a sample Cambridge mark scheme once again for a similar 3-mark question in Q8(b), 2 marks are awarded for all 6 points correctly plotted while 1 mark is awarded for at least getting 4 points right.

If (and that's a big if) the same mark scheme is applied to your case, you'll probably get one mark taken away for plotting that point wrongly.

Regarding your gradient, see above.

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Is it necessary to write down the workings for 10(a)(ii)-mean and standard deviation to get the marks? I used my calculator to get the answers.

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@Discuss: From Miss Loi's experience with the mark schemes of Singapore's schools, it should be fine to simply state the final answer after arriving at it by the calculator method -

providedyou got it right.HOWEVER, by doing so you'll have no method mark(s) to fall back on should you somehow get it wrong through punching the wrong key(s) etc. so it's definitely a good idea to at least show your workings like what's written in the solutions - especially so for that 2-mark part (ii)!曜

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Hi Miss Loi, I have a few question ask ask you.

1) Question 2(a)(i) If i leave the answer as 6.3 l (Short form for litre) and not litre/100km, i will only get 1 mark right?

2) Question 5(ii) Is it a must to write 'The n'th term is 11 term'? I just leave my answer as 11.

3) Question 7(b)(Ii) If i never add the base area, i will get 2 marks?

4) Question 8(b)(iii) Can i write ' O,X and Y are collinear. OX=1/2OY'

5) Question 9(d) My gradient is 2.56, is it acceptable?

6) Question 10(a)(ii)(b) If i just use calculator to get S.D, i will only get 1 mark?

Thank you (:

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@Hilda: 1) It's fair to say you'll get a −1 due to wrong unit since Q2(a)(ii) clearly requires you to "give your answer in litres per 100 km".

2)

Strictly speakingyou should clearly reference the 11th term in your answer, but it all boils down to how strict Cambridge is on this.3) See above.

4) To be honest, Miss Loi wrote

OX= ½OXat first but changed it to "Xis the midpoint ofOY" for this reason.5) See above.

6) See above!

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Hi

Do you think 90% will be enough for an A1.

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MISS LOI ，i honestly want to ask you : A1 must be above 90%? if above 85% ,can i get A1 ?how much possibility if i get 85% above to get A1. THX ,begging for your reply.........

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@chamberlain: A2 already gd liao la =.= , i only get 80 only leh , T.T

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@yoyoyo: no!!!!! if i cannot get A1 ,i will die .GOD BLESS ME PLZ

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@chamberlain: haha y die leh? parents scold ar?

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I didn't state my reasons for the angle question3b because it is only 1 mark each. Will i still get it correct?

And for question 5a(ii) i wrote T11. will i be marked down as well?

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@Desperato:

Strictly speaking, reasons should be stated as part of your workings in Q3(b)(i) but since they only carry a mark each, it'll depend on how particular Cambridge is on this.As for Q5(a)(ii), opinions might vary but Miss Loi feels that

T_{11}is a clear enough reference to the 11^{th}term. This, after all, is a maths paper.曜

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hope tis year , dey dont glgl go anyhw adjust moderation till we emo la =.=

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Hi Miss Loi,

First of all, thanks for the answers to both paper 1 and paper 2! They have been a great help to me and my classmates.

I have a couple of questions regarding the answer(s) to the papers.

1) Question 2a (ii) (a), should the answer be rounded up or down? Since the question asks for the distance that she can travel, I thought that it should be rounded down instead of up.

2) Question 9, would I be penalised for writing the answers on a piece of foolscap paper?

3) Question 10b (i), I was told by my teacher that if you are asked to complete the probability tree, the answers on the tree must be in it's simplest form. Was I supposed to leave it in it's x/9 and x/10 form or change it to it's simplest form?

Thank you.

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@Greg: graph ans write on foolscape of cuz will penalize la =.=

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@Greg: *rubs eyes at yet another missed comment!*

1) This kinda thing huh ... we (and most others) have rounded up since, technically, we've been instructed to give all non-exact answers to 3 sf when the degree of accuracy isn't specified. In this aspect, it's perfectly fine to say she can travel

approximately732 km (make sure you use the ≈ sign).But if you round

down, logically you're not wrong in this context but Miss Loi is just worried that a 'robotic' marker may not see it your way - so you'd be wise to state your reason clearly in order to to cover yourself.2) For Q9 - on the contrary Miss Loi would like to believe that Cambridge markers are kindly, compassionate folks who are not particular about such things as long as they can see your workings!

3) No need

lah- even the probabilities on the question paper are not in the simplest form!曜

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Hello, Miss Loi

Would I be penalized for using the equal sign when rounding off my answer instead of the rounding off sign?

And would I be penalized for using calculator to get the standard deviation for question 10?

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@Randomness: *clears throat for the upteenth time*

STRICTLY speaking, ≈ should be used whenever you round-off non-exact values but [starts robotic tone]`but it all boils down to how strict Cambridge is on this`

[ends robotic tone]For Q10, see above.

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i'm very scared that i'll fail my maths. i usually get D7s. i found the o level maths papers easy but when i look at the solutions, i made soooo many careless mistakes & now i'm worrying like crazy. i wonder how the moderation will be like since most the peeps around me are scoring as high as 90, some even getting full marks. i don't want to end up failing T.T i really put in a lot of hard work, i don't mind getting a C6 cos i never passed math since sec 2. ughhh

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Hi, erm im not a student here & im not sure if this will be answered, but I would like to ask you what is ur view on the A1 mark for this year? Taking into consideration the good schools& the neighbourhood ones. Much appreciated. Thanks

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@Nigel Woon: 90% can get A1

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Hi ms Loi,i know this is a VERY late comment but i just want to ask you if we will get penalised if we use 3.sf numbers in workings but got the coorect answer in the end as i used stored numbers?

## 5 Reactions

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2011 Emaths Paper 2 solutions air-dropped: http://t.co/yfrjT4FS #emath #olevel Please be gentle with me on all those little sig. fig. etc ..

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@NatKimKEY http://t.co/g4lXTglk

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2011 Emaths Paper 2 solutions air-dropped: http://t.co/yfrjT4FS #emath #olevel Please be gentle with me on all those little sig. fig. etc ..

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2011 Emaths Paper 2 solutions air-dropped: http://t.co/yfrjT4FS #emath #olevel Please be gentle with me on all those little sig. fig. etc ..

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@JOSEOBISM RT @xoInfinite: For clearer EM p2 solutions & answers: http://t.co/SDMVSTUw