Mathematics: Post your doubts here!

[littlecloud11]

The volume ,V cm^3 of a sphere of a radius r cm,is given by the fromula V=4/3 pie r^3. A pump put air into a second spherical baloon at the rate of 1200 cm^3/s.Calculate the rate in cm/s, at which the radius is increasing at the instant when radius is 5 cm?
I hope someone will solve this

dV/dr = 3* 4/3π r^2 dV/dt= 1200 cm^3/s
= 4πr^2
dr/dt = dr/dV * dV/dt
dr/dt = [1/(4πr^2)] * 1200
substitute r=5
dr/dt = [1/(4π *25)] *1200
dr/dt =3.82 cm/s

 

[usman]

A facebook group for Further Maths, intended to remove your doubts and solve your problems. Check it out:-

http://www.facebook.com/groups/furthermathsprodigies/​

 

[parthrocks]

Hello friends....I have a small doubt in aths...what is the modulus of -5????

 

[parthrocks]

Can anyone help me with co prime numbers which are also said as relatively prime number??? Ho2 do u find out the ways that can be expressed? ?

 

[asexamskillme111]

http://papers.xtremepapers.com/CIE/...AS Level/Mathematics (9709)/9709_w04_qp_4.pdf

Q6. I don't get why in the marking scheme they only consider Fmax of the box on top. Help please.

 

[parthrocks]

Can anyone help me with co prime numbers which are also said as relatively prime number??? Ho2 do u find out the ways that can be expressed? ?

 

[parthrocks]

Can anyone help me with co prime numbers which are also said as relatively prime number??? Ho2 do u find out the ways that can be expressed? ?

 

[parthrocks]

Can anyone help me with co prime numbers which are also said as relatively prime number??? Ho2 do u find out the ways that can be expressed? ?

 

[parthrocks]

Can anyone help me with co prime numbers which are also said as relatively prime number??? Ho2 do u find out the ways that can be expressed? ?

 

[Dug]

Assalamoalaikum Wr Wb!

Post your doubts here. Make sure you give the link to the question paper when posting your doubts.


May Allah give us all success in this world as well as the HereAfter...Aameen!!

And oh yeah, let me put up some links for A level Maths Notes here.

Check this out! - Nice website, with video tutorials for everything! MUST CHECK

My P1 Notes! - Only few chapters available at the moment!

Maths Notes by destined007

Some Notes for P1 and P3 - shared by hamidali391

A LEVEL MATHS TOPIC WISE NOTES

MATHS A LEVEL LECTURES

compiled pastpapers p3 and p4 - by haseebriaz

Permutations and Combinations (my explanation)- P6

Permutations and Combinations - P6

Vectors - P3

Complex No. max/min IzI and arg(z) - P3

Sketcing Argand Diagrams - P3 (click to download..shared by ffaadyy)

Range of a function. - P1

Add this to the collection.

 

[*MK*skydiver :D]

Can someone please help me in this :
Q1 Mechanics 2
http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Mathematics (9709)/9709_w09_qp_52.pdf
Thanks!

Can someone please solve this for me asap ?


and this too
http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Mathematics (9709)/9709_s10_qp_53.pdf # 4 , i cant understand how to get the distance of centre of mass from A ?! :S

 

[asexamskillme111]

http://papers.xtremepapers.com/CIE/...AS Level/Mathematics (9709)/9709_w04_qp_4.pdf

Q6. I don't get why in the marking scheme they only consider Fmax of the box on top. Help please.

 

[GorgeousEyes]

can any one help me with June 2005 Q7 iii
June 2009 Q10 ii - iii
Math As pure.

 

[GorgeousEyes]

http://papers.xtremepapers.com/CIE/...AS Level/Mathematics (9709)/9709_w04_qp_4.pdf

Q6. I don't get why in the marking scheme they only consider Fmax of the box on top. Help please.

They told you in the question there's no sliding between the two boxes . so the friction between them didn't exceed the maximum to make them move . so f is less or = 0.4x400 . by using newtons law : 400a < or = 1600
There's no driving force on the upper box .
Hope i helped

 

[Rutzaba]

Can anyone help me with co prime numbers which are also said as relatively prime number??? Ho2 do u find out the ways that can be expressed? ?

dude u post a question hre once and once ok? we will find u k?

 

[farhan143]

I have a difficulty in solving q-6, b (i) of O/N 2012


can someone explain me, how to solve it..
not just the solution..
the explanation as well

THANKS in adavance.
FARHAN

 

[Dug]

I have a difficulty in solving q-6, b (i) of O/N 2012
View attachment 22407

b. (i)
Because it looks less tedious, I am going to find the no. of arrangements where the number is odd and then subtract it from all possible arrangements.

For odd numbers, the last digit has to be odd. This gives us two possibilities.

_ _ _ _ _ _ 1 or _ _ _ _ _ _ 7

No. of odd arrangements = (6!/2!) + (6!/2!) = 720

No. of even arrangements = No. of all possible arrangements - No. of odd arrangements
= 7!/2! - 720
= 1800

 

[snowbrood]

Prove that if (c-b).a=0 and (c-a).b=0, then (b-a).c=0. Show this can be used to prove the following geometric results:
1) The lines through the vertices of a triangle ABC perpendicular to the opposite sides meet in a point (the orthocentre)
2) The tetrhedron OABC has two pairs of perpendicular opposite edges, the third pair of edges is perpendicular.
Prove also that, in both cases, OA^2 + BC^2 = OB^2 + CA^2 = OC^2 + AB^2.

 

[PhyZac]

Assalamu Alikum Wa Rahmatullahi Wa Barakatoho...littlecloud11
Can someone solve Question 6 part (i)

http://papers.xtremepapers.com/CIE/...S Level/Mathematics (9709)/9709_s10_qp_32.pdf

 

[littlecloud11]

Assalamu Alikum Wa Rahmatullahi Wa Barakatoho...littlecloud11
Can someone solve Question 6 part (i)

http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Mathematics (9709)/9709_s10_qp_32.pdf

Re-arrange the eq-
ln y = 2x+1/x
differentiate both sides
1/y dy/dx = [2x- 1(2x+1)]/x^2 {use u/v formula for RHS and ln y = 1/y dy/dx for LHS}
1/y dy/dx = 2x-2x -1/ x^2
1/y dy/dx = -1/x^2
dy/dx = (-1/x^2)/ (1/y)
dy/dx = -y/x^2