O-Level Additional Math

[Dharma]

Muffins:

iFruit:

[quote=\"Muffins\"]woah..... these questions making my head spin already :faint: :faint:

Welcome to the real world mate ! We have no Mohammads and Alis exchanging marbles or silly old mothers trying to pick up their daughters from the schools at constant speed every day here.

How, I wish, school would get easier as we advance in age.....

iFruit:

We just have beautiful x's and y's and before you blink sin As, cos Bs and Sec Cs.

I thought there was sine, cosine, and a tangent???? what's a Sec???[/quote]Hi Muffins,

sec A = 1/ cos A ...... (sec is short form for secant)

[tianzhu]

Hi


Just a quick survey,how do you find secondary one Maths?
Is it less demanding or easier than PSLE Maths?

Best wishes

[hashroop]

pls advise where can i get hold of Sec 2math exam papers(express) of top schools. Something like they have for primary school.

[ilovechamomile]

You can try Bras Basah Complex. I think there’s a shop that compiles exam papers of top schools and put out for sale.

[teddy7171]

Plz help!


The scale of map P is 1/p and the scale of map Q is 1/q. Suppose a street is represented by lines of 12cm long and 16cm long on maps P and Q respectively.
a) find p/q and express the answer in the simplest form.
b) if p=5000, find (i) the value of q, (ii) the actual length, in m, of the street.
c) if p=5000 and the actual area of a plot of land in 2812.5metre square, calculate its area on (i) map P and (ii) map Q.

TIA.

[tianzhu]

teddy7171:

The scale of map P is 1/p and the scale of map Q is 1/q. Suppose a street is represented by lines of 12cm long and 16cm long on maps P and Q respectively.
a) find p/q and express the answer in the simplest form.
b) if p=5000, find (i) the value of q, (ii) the actual length, in m, of the street.
c) if p=5000 and the actual area of a plot of land in 2812.5metre square, calculate its area on (i) map P and (ii) map Q.

Hi

I did some reading using my boy’s textbook and will attempt to answer your question.

a)A scale of 1:p means that 1cm represents pcm
Therefore 12cm represent 12pcm in map P
Likewise, 16cm represent 16qcm in map Q
12p=16q
Hence p/q = 4/3

b)q = 3750
The actual length of the street is 12*5000 = 600m

c)For map P
1cm represents 50m
1 cmsq represents 2500 cmsq
2812.5/2500 = 1.125 cmsq

For map Q
1cm represents 37.5m
1 cmsq represents 1406.25 cmsq
2812.5/1406.25 = 2 cmsq

Are my answers correct?

Best wishes

[teddy7171]

a)A scale of 1:p means that 1cm represents pcm

Therefore 12cm represent 12pcm in map P
Likewise, 16cm represent 16qcm in map Q
12p=16q
Hence p/q = 4/3

b)q = 3750
The actual length of the street is 12*5000 = 600m

c)For map P
1cm represents 50m
1 cmsq represents 2500 cmsq
2812.5/2500 = 1.125 cmsq

For map Q
1cm represents 37.5m
1 cmsq represents 1406.25 cmsq
2812.5/1406.25 = 2 cmsq

Are my answers correct?

Best wishes[/quote]


Hi Tianzhu,
My boy does not have the answers for the question and doesn’t know how to solve it.

His answer for (a) is 3/4 instead.

Please enlighten us how do u arrived at 4/3 and q = 3750.

Sorry for the trouble and thanks.

[tianzhu]

Hi teddy7171


In order to solve this question, students need to understand the concepts of Scales and Maps. You may refer to your son’s textbook for a more detailed explanation.

A scale of 1:p means that 1cm represents pcm
Therefore 12cm represent 12pcm in map P

Likewise, 16cm represent 16qcm in map Q

The same street is represented by different scales as in map P and Q
12p=16q
Hence p/q = 4/3

Here p is given as 5000
p/q = 4/3
5000/q = 4/3
Hence q = 15000/4 = 3750

Best wishes

[Sahimi]

Hi! pls help!!


If n is a number, show that for all values of n, (n3 + 11n) is divisible by 6. (sec Two maths)
Thks

[iFruit]

Sahimi:

Hi! pls help!!


If n is a number, show that for all values of n, (n3 + 11n) is divisible by 6. (sec Two maths)
Thks

n³ + 11n = n³ -n + 12n = n(n²-1)+12n = n(n-1)(n+1)+12n = (n-1)n(n+1)+12n


(n-1)n(n+1) is the product of 3 consecutive numbers which is always divisible by 6 ( you can use induction to prove if necessary) and 12n is divisible by 6.

So, n³ + 11n is divisible by 6

HTH