O-Level Additional Math

[YLH88]

[quote]
mrswongtuition wrote :
My sis' Maths was terrible too. We got a HOD Maths from a Secondary school to coach her 1-to-1 for E & A Maths. She got A2 for E Maths and B3 for A Maths. Very good for my sister who used to fail A Maths and borderline pass E Maths.

If you are willing to spend on a good tutor, it's not too late now. Still have 9+ months to prepare [/quote]Hi mrswongtuiton,

I would like to have the contact for the Maths tutor. Have just pm you.

Thank you.

[OK Lor]

Hi CoffeeCat,


Thanks for Q1. Please help to comment on Q2:

f(x) = 9/(1+cos2x) + 25/(1-cos2x) = 9/[2(cos x)^2] + 25/[2(sinx)^2]
= [9(sec x)^2 + 25(cosec x)^2] / 2
f'(x) = 9[(sec x)^2](tan x) - 25[(cosec x)^2](cot x) = 0
9[(sec x)^2](tan x) = 25[(cosec x)^2](cot x)
(tan x)^4 = 25 / 9
tan x = (5/3)^(1/2); cos x = (3/8 )^(1/2), sin x = (5/8 )^(1/2).
Least possible value of f(x) = [9(8/3) + 25(8/5)] / 2 = 32 ?

Thanks.

[Muffins]

Just a question to ask. For my exam, I had gotten a question like this:


a) Express 756 in its index form

b) Hence, find the value k where 756k is a perfect square.

I had gotten part a) correct, but I had put 2⅓ for part b), but they marked me wrong, saying that the answer was 21. Could anyone explain why? Thanks.

[Vanilla Cake]

Muffins:

Just a question to ask. For my exam, I had gotten a question like this:


a) Express 756 in its index form

b) Hence, find the value k where 756k is a perfect square.

I had gotten part a) correct, but I had put 2⅓ for part b), but they marked me wrong, saying that the answer was 21. Could anyone explain why? Thanks.

756=2²x3³x7
(a) 756 in its index form = 2²x3³x7

Perfect square =2²x3⁴x7²
k = 3x7 = 21

(b)Value of k where 756k is a perfect square = 21

Pls do not :offtopic:

[atutor2001]

Muffins:

Just a question to ask. For my exam, I had gotten a question like this:


a) Express 756 in its index form

b) Hence, find the value k where 756k is a perfect square.

I had gotten part a) correct, but I had put 2⅓ for part b), but they marked me wrong, saying that the answer was 21. Could anyone explain why? Thanks.

There is probably a requirement in the question that \"k is a whole number, find the smallest value of k\", which is why your answer is not acceptable

[CoffeeCat]

OK Lor:

Hi CoffeeCat,


Thanks for Q1. Please help to comment on Q2:

f(x) = 9/(1+cos2x) + 25/(1-cos2x) = 9/[2(cos x)^2] + 25/[2(sinx)^2]
= [9(sec x)^2 + 25(cosec x)^2] / 2
f'(x) = 9[(sec x)^2](tan x) - 25[(cosec x)^2](cot x) = 0
9[(sec x)^2](tan x) = 25[(cosec x)^2](cot x)
(tan x)^4 = 25 / 9
tan x = (5/3)^(1/2); cos x = (3/8 )^(1/2), sin x = (5/8 )^(1/2).
Least possible value of f(x) = [9(8/3) + 25(8/5)] / 2 = 32 ?

Thanks.

sounds correct to me ...

[OK Lor]

Hi 高人 CoffeCat,


Thanks.

[Muffins]

atutor2001:

Muffins:

Just a question to ask. For my exam, I had gotten a question like this:


a) Express 756 in its index form

b) Hence, find the value k where 756k is a perfect square.

I had gotten part a) correct, but I had put 2⅓ for part b), but they marked me wrong, saying that the answer was 21. Could anyone explain why? Thanks.

There is probably a requirement in the question that \"k is a whole number, find the smallest value of k\", which is why your answer is not acceptable

Hi atutor2001, this was actually the exact question itself,, nothing missed out.... :sad:

[Muffins]

Vanilla Cake:

Muffins:

Just a question to ask. For my exam, I had gotten a question like this:


a) Express 756 in its index form

b) Hence, find the value k where 756k is a perfect square.

I had gotten part a) correct, but I had put 2⅓ for part b), but they marked me wrong, saying that the answer was 21. Could anyone explain why? Thanks.

756=2²x3³x7
(a) 756 in its index form = 2²x3³x7

Perfect square =2²x3⁴x7²
k = 3x7 = 21

(b)Value of k where 756k is a perfect square = 21

Pls do not :offtopic:

Hi VC, thanks for the answer, but I wanted to know the explanation as to why my answer was not allowed. It is, in fact, a smaller value than 21, which still makes 756 a perfect square.... TIA.

[Vanilla Cake]

Hi Muffins,

Sorry, I don't know how to explain.Better go and ask your teacher when school reopens.


BTW,my younger sister is taking part in http://www.acs.sch.edu.sg/acs_indep/announcements.php?id=93 for All Singapore Primary Schools 2010.Do you know whether ACSI sell the worked solutions for the past years' questions of Mathlympics?Do let us know your findings.
Thanks.