Mathematics: Post your doubts here!

[_Ahmad]

still don't understand...can u solve it on paper and send photo plz?explain the other question also

In the first part (for 36 values)
Σ(x − 45) = −148 and
Σ(x − 45)^2=3089

Now for finding sd of 37 values we need new Σ(x − 45) and Σ(x − 45)^2
x=29

(x-45)=29-45=-16
so new Σ(x − 45)= -148+(-16)=-164

(x-45)2=(29-45)^2=256
So new Σ(x − 45)^2 =256+3089=3345

now you got new values of Σ(x − 45) and Σ(x − 45)^2
so just apply the formula of sd to get the answer

Hope you got it

 

[ZaqZainab]

still don't understand...can u solve it on paper and send photo plz?explain the other question also

both my cam and mobile are out of charge
what part don't you get?

 

[_Ahmad]

ZaqZainab

can you please solve my doubt

 

[ZaqZainab]

http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Mathematics (9709)/9709_s13_qp_63.pdf Q6 (iii)
http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Mathematics (9709)/9709_s11_qp_63.pdf Q3 (iii)
http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Mathematics (9709)/9709_s11_qp_61.pdf Q6 (iv)

In these above listed questions for finding mean we make intervals. So can you please tell how to make intervals in these questions.

intervals for what?
the frequencies? the weights?
let me tell you what i do
for example Q6(iii)
For the weight which is x
add first with the second /2 and so on
so here (40+50)/2, (50+60)/2 , ...................<---x values
now for the frequencies
the second- first
so here
(12-0),(34-12).................
and then i use the equation in the data booklet mean= sum of fx /f

 

[_Ahmad]

Weight (x kilograms) for the (first paper)
Mark (for the second paper)
Number of pupils in a school (for third paper)

 

[ZaqZainab]

Weight (x kilograms) for the (first paper)
Mark (for the second paper)
Number of pupils in a school (for third paper)

For the weight which is x
add first with the second /2 and so on
so here (40+50)/2, (50+60)/2 , ...................<---x values

and then i use the equation in the data booklet mean= sum of fx /f

for the first paper
for second
(10+20)/2 , (20+35)/2..........
for the third
100+150/2, 150+200/2 and so on
this is how i get x values

 

[_Ahmad]

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

Can anyone PLEASE explain Q3 ii)

 

[Tanvir Azad]

help!!! please its urgent... i need to solve this before 20th May.. I wud be really grateful.. :/

 

[moonangel996]

HELP PLEASE!!
http://papers.xtremepapers.com/CIE/...S Level/Mathematics (9709)/9709_s11_qp_61.pdf
^ Question 6 ( iv )why did the add 0.5 to the mid-value ???
while in this one
http://papers.xtremepapers.com/CIE/...S Level/Mathematics (9709)/9709_s11_qp_63.pdf
^ Question 3 ( iii ) they subtracted 0.5 from the mid-value ??
when do we add 0.5 and when do we subtract 0.5 from the mid-value ?? when do we leave the mid-value as it is ??

 

[saadgujjar]

In the first part (for 36 values)
Σ(x − 45) = −148 and
Σ(x − 45)^2=3089

Now for finding sd of 37 values we need new Σ(x − 45) and Σ(x − 45)^2
x=29

(x-45)=29-45=-16
so new Σ(x − 45)= -148+(-16)=-164

(x-45)2=(29-45)^2=256
So new Σ(x − 45)^2 =256+3089=3345

now you got new values of Σ(x − 45) and Σ(x − 45)^2
so just apply the formula of sd to get the answer

Hope you got it

great....thnx....and explain also the other question of combination

 

[Rutzaba]

http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Mathematics (9709)/9709_s12_qp_32.pdf

Q9 .... part ii

How do we integrate that?

substitute ln x as a when a=lnx x=e^a
then integrate
e^a (a^2)
double by parts

 

[saadgujjar]

View attachment 42612 help!!! please its urgent... i need to solve this before 20th May.. I wud be really grateful.. :/

is answer 1,1

 

[Lostsoul]

Part 2 with working pls

 

[Lostsoul]

View attachment 42626 Part 2 with working plsView attachment 42626

 

[Rutzaba]

u=cosx
du/dx= -sinx
dx= -du/sinx
change limits
if u =cosx
and x=pi/2
uper limit u=o
x=0
lower limit u=cos0=1
integrate
5sin^3 cos^2 * -du/ sin
cancelling sin
-5sin^2 cos^2 du
remember that 1-cos^2=sin^2
-5(1-cos^2)(cos^2) du
-5(1-u^2)(u^2)
-5(u^2 -u^4)
now integrate for0 to 1
-5( u^3)/3 +5(u^5)/5 put 0 to 1
0-(-5( u^3)/3 +5(u^5)/5 )
2/3 :/ wats the ans
Lostsoul

 

[Rutzaba]

View attachment 42626 Part 2 with working plsView attachment 42626

doing it ^

 

[Lostsoul]

What about the sinx^3?
How dyu turn it to u?
Can you show me rhe full answer pleaaaassseee

 

[Rutzaba]

What about the sinx^3?
How dyu turn it to u?
Can you show me rhe full answer pleaaaassseee

i did wats the ans?

 

[Lostsoul]

Integral5(u^2 -u^4)
Final answer 2/3

I dont know substitution for integration

 

[Lostsoul]

i did wats the ans?

Just saw it
Thaaankksss!!!