Mathematics: Post your doubts here!

[reina81]

MJ08, P3, Q 5 and Q6, Q8
Yes it's a lot i know
http://www.xtremepapers.com/papers/CIE/Cambridge International A and AS Level/Mathematics (9709)/9709_s08_qp_3.pdf

http://www.xtremepapers.com/papers/CIE/Cambridge International A and AS Level/Mathematics (9709)/9709_s08_ms_3.pdf

 

[Jimmy Russels]

hey, don't laugh at me. gonna post something stupid here.

x+y = 12. what is the maximum value of xy?

 

[reina81]

hey, don't laugh at me. gonna post something stupid here.

x+y = 12. what is the maximum value of xy?

is this from a pastpaper?

 

[Yours Truly]

hey, don't laugh at me. gonna post something stupid here.

x+y = 12. what is the maximum value of xy?

No one's gonna laugh at you, don't worry

Try the possible combinations of xy:

1 * 11 = 11
2 * 10 = 20
3 * 9 = 27
4 * 8 = 32
5 * 7 = 35
6 * 6 = 36

So the max value is 36

 

[Jimmy Russels]

No one's gonna laugh at you, don't worry

Try the possible combinations of xy:

1 * 11 = 11
2 * 10 = 20
3 * 9 = 27
4 * 8 = 32
5 * 7 = 35
6 * 6 = 36

So the max value is 36

Can you solve using derivatives?

 

[anonymous123]

Can someone please help me in this question of Oct/Nov 2010 paper 11 Ques 5?

For the angle ACB
we need vectors CA and CB
CA = 6i - 10k
CB = 8j - 10k

CA.CB = |CA| x |CB| costheta

CA.CB=(6i-10k)(8j-10k) = 100
|CA| = √6^2 + (-10)^2 = √136
|CB| = √8^2+(-10)^2 = √164

put values in formula
100 = √136 x √164 x costheta
costheta = 0.66958
theta = 48.0

 

[2pac]

Can somebody please explain me q9 of 9709 may 2009 p3.
Have just started solving vector questions and find myself only capable of deducing the intersection points,so really need some urgent help.
thanks

 

[redapple20]

two machines,machine 1 and machine 2, produce shirt buttons. random sample of 80 buttons are selected from the output of each machine and each button is inspected of faults.
the sample from machine 1 contained 8 faulty buttons and that frm machine 2 ,19 faulty buttons!
(a) calculate a 90%confidence intervals for proportions,p1 and p2,of faulty buttons produced by each machine.
plx help any 1! this is s2.

 

[hm12]

http://www.xtremepapers.com/papers/...S Level/Mathematics (9709)/9709_s10_qp_11.pdf

please explain question 1 part(ii) and part(iii)

 

[anonymous123]

http://www.xtremepapers.com/papers/CIE/Cambridge International A and AS Level/Mathematics (9709)/9709_s10_qp_11.pdf

please explain question 1 part(ii) and part(iii)

its answered on page 86

 

[hm12]

its answered on page 86

thanks for telling

 

[leadingguy]

http://www.xtremepapers.com/papers/...S Level/Mathematics (9709)/9709_w09_qp_61.pdf

http://www.xtremepapers.com/papers/...S Level/Mathematics (9709)/9709_w09_ms_61.pdf

Question 3 part 2 can Any one explain that what the daTa given represents (standard short long)

and explain also that what is beinG asked in this part of the question???

plx It wil be gr8 help if any one couLd saY SomE

 

[Esme]

Jazakallah nikesh


sm1 clear my doubt plz?

It depends on your domain.suppose the x coordinate of the vertex is a. now if your domai is x>a then the square root sign will be positive . however if it is x<a then the sign will be in negative.

 

[anonymous123]

It depends on your domain.suppose the x coordinate of the vertex is a. now if your domai is x>a then the square root sign will be positive . however if it is x<a then the sign will be in negative.

is dat always the case? m relying on ur ans tym is short

 

[CaptainDanger]

if u see the completed square form of f(x) is (x-2)^2+3.
now as g(x) is x-2. h(x) will be x^2+3. becuz then we put the equation of gx in hx n then we get fx.

Sorry. I don't get it ?

 

[leadingguy]

http://www.xtremepapers.com/papers/CIE/Cambridge International A and AS Level/Mathematics (9709)/9709_w09_qp_61.pdf

http://www.xtremepapers.com/papers/CIE/Cambridge International A and AS Level/Mathematics (9709)/9709_w09_ms_61.pdf

Question 3 part 2 can Any one explain that what the daTa given represents (standard short long)

and explain also that what is beinG asked in this part of the question???

plx It wil be gr8 help if any one couLd saY SomE

solve above question plz and
solve the below one too question 1 part 2 I gt 5! in numenator and 4 in the denominator but unable to get 4! in numenator plz help
http://www.xtremepapers.com/papers/CIE/Cambridge International A and AS Level/Mathematics (9709)/9709_w04_ms_6.pdf
http://www.xtremepapers.com/papers/CIE/Cambridge International A and AS Level/Mathematics (9709)/9709_w04_qp_6.pdf

 

[Zephyro]

hey, don't laugh at me. gonna post something stupid here.

x+y = 12. what is the maximum value of xy?

Solved it via algebra if you still want it.

y = 12 - x

xy = 12 -x (x )
= 12x - x^2

Let xy = u

du/dx = 12 - 2x

du/dx = 0

12 - 2x = 0
x = 6

Double deravative to confirm its maximum.

-2 = Negative, so maximum.


as you can see from the start y = 12 - x
y = 6 aswell


Maximum value = 6*6 = 36

 

[smzimran]

solve above question plz and
solve the below one too question 1 part 2 I gt 5! in numenator and 4 in the denominator but unable to get 4! in numenator plz help
http://www.xtremepapers.com/papers/CIE/Cambridge International A and AS Level/Mathematics (9709)/9709_w04_ms_6.pdf
http://www.xtremepapers.com/papers/CIE/Cambridge International A and AS Level/Mathematics (9709)/9709_w04_qp_6.pdf

Q1(ii)
First arrange the consonants with gaps in between

There are 5! / 2! arrangements for consonants (divide by 2! because of 2 'N' present)

For the first vowel, there are 4 possible locations, as seen in the diagram
For the second, there are 3,
for the third there are 2 and so on

In short, the arrangements of vowels are 4! / 2! (divide by 2! because of 2 'A' present)

So,
The answer
= (5! / 2!) * (4! / 2!)
= 720

 

[Esme]

is dat always the case? m relying on ur ans tym is short

you dont believe me ??
there you go...Proof!

 

[Esme]

Sorry. I don't get it ?

ummmm..... ok lemme try again

fx is (x-2)^2+3. and gx is (x-2). so in wat function will u subsitute (x-2) in order to get(x-2)^2+3
? that will be x^2+3 which is hx. now subsitute (x-2) in the funstion x^2+3 and you will get (x-2)^2+3. therefore your fx=h(gx).
sorry its a little confusing.