Mathematics: Post your doubts here!

[pratikdahal]

Thanks in advance..!!
question no. iii

 

[yuliana95]

Hi.. I really need help in Mechanics 1 here.. it's about motion due to gravity.URGENT
Here is the question(I put them in italic):
When an object falls through a liquid, three forces act on it: its weight, the buoyancy and the resistance of the liquid. Two spheres, of mass 1/2 kg and 3/2kg respectively, have the same radius, so that they have the same buoyancy of 3.2N and the same resistance formula, 5v newtons when falling at speed v m/s. Both spheres enter the liquid falling vertically at 1 m/s. Calculate the terminal speeds of the two spheres, and the acceleration or deceleration when they enter the liquid. Using the same axes, sketch (t,v) graphs for the two spheres.
If the depth of the liquid is 10m, show that the heavier sphere reaches the bottom after a time between 4 and 10 seconds. Find bounds for the time that lighter sphere takes to reach the botton.

Thanks a lot guys..

 

[IgoforA]

http://www.xtremepapers.com/CIE/Interna ... 8_qp_3.pdf
can anyone help me with this paper... it took me about 2 hrs already solving no1 to 7... it's really hard... help me with no 7 please.. why is it division?? & thank you

 

[makaveli]

do i have to study p2 when i prepare for p3?

 

[ks136]

do i have to study p2 when i prepare for p3?

depends on ur subject combination

 

[DaEconomist]

Need Help on AS maths questions concerning Volumes of Revolution around y-axis.

Q1. The region enclosed between the graphs of x=2 and the curve y=1/8x^2+2 is rotated about the y-axis to form a solid. Find the volume of the solid.
Q2. The region enclosed between the graphs of y=x^1/2 and y=x^2 is denoted by R. Find the volume generated when R is rotated through 360 degrees about the y-axis.

A1. 3/10 Pi
A2. 9 Pi

Any help will be appreciated

thanks

 

[dragoninja98]

can someone please send me notes/links on quadratic functions ?
and is preparing from pastpapers in the first year a good idea ?

 

[Muhammad Talha]

AoA....
Plz help me in this ques...:
(i) Find the number of ways in which all twelve letters of the word REFRIGERATOR can be arranged:
(a) if there are no restrictions.
(b) if the R's must all be together.
(ii) How many different selections of four letter from the twelve letters of the word REFRIGERATOR contains no R's and two E's??

 

[IgoforA]

m/j 2009... paper 3
help me with no 4... part 3.. what no. will i begin with, is it 1 or 2 and why??
no. 6 part 2 and 3
and no 9 part 2

Please help my previous post and this, i'm gonna have the exam at the end of the month.

 

[markskoop]

[email protected] first answer would be (12!/4!*2!)=9979200.this is because 4 R are being repeated and 2 E being repeated.

next answer would be (9!/2!)=181440 .....as its said R must be together so taking 4 R as 1,the total arrangement would be 9! and den as 2 E are being repeated in dis case too we will write.......(9!/2!)

the oder last answer would be 6C2.......this is coz when we donot put r in d arrangementwe will hav total letters of 8...and it is even said that the arrangement should contain 2 E..........so now fr formin 4 digits we jus need two more digits form 6 digitS(AFTER DEDUCTING R AND E)hence the answer would be 6C2.........hope u understand.......

 

[madan159]

HEPL ME Q.NO. 9 (II) ITS VERY DIFFICULT TO SOLVE FOR ME... :Yahoo!: :wink:

 

[DaEconomist]

http://www.xtremepapers.com/CIE/Interna ... _qp_61.pdf

Question 7i and 7ii please

Any help will be appreciated

thanks

 

[markskoop]

for 7(i).
p(at least one 3)=p(x>=1)
1-p(x=0)
1-(9C0*(5/6)^9)=0.806

for 7(ii).
we don't know the no.of throws which we suppose as n......
so
instead of 9 in d first solution,we take it as n....then
1-(9C0*(5/6)^n)>0.or,,,(5/6)^n<0.1
then u can take log in both sides and do or simply frm calculator to get the ans n=13

hope u understood...............

 

[jihan911]

help question paper 9709/63/O/N/10...question number 7 (ii) explain me the answer plzz

 

[IgoforA]

is there anyone who can help us??

 

[markskoop]

hey.i really got a confusion in writing the intervals while makin cumulative frequency grap.............the upper limit of each interval should be inclusive or exclusive??xplain me wid xamples.............and do we need to arange the upper and lower limits whil calculating mean???answr........................... :unknown:

 

[Muhammad Talha]

[email protected] first answer would be (12!/4!*2!)=9979200.this is because 4 R are being repeated and 2 E being repeated.

next answer would be (9!/2!)=181440 .....as its said R must be together so taking 4 R as 1,the total arrangement would be 9! and den as 2 E are being repeated in dis case too we will write.......(9!/2!)

the oder last answer would be 6C2.......this is coz when we donot put r in d arrangementwe will hav total letters of 8...and it is even said that the arrangement should contain 2 E..........so now fr formin 4 digits we jus need two more digits form 6 digitS(AFTER DEDUCTING R AND E)hence the answer would be 6C2.........hope u understand.......

Thank u soo much....

 

[XPFMember]

Assalamoalaikum!

Well I'm confused about the questions when it says which of the mean, median or mode is a preferable measure of central tendency...

I don't understand these? How are we supposed to answer them?!

 

[1357913579]

see its really simple as we know that we use mean mode and median to measure central tendency but after seing and analizing the question we can comeout with a conclution which of thess can we use so we just see what is the mode and mean if they are not in middle for instance midle no. is 50 and mode is 10 mean is 14 so we cannot use them this will ussually occur when there is when one big value which will chenge te whole solution so in those case only median is sutaible median would be always suitable as it everytime gives the middle term no matter number even if there is one very big number with other small number hope i helped

 

[IgoforA]

please help