[rbnphlp]

(Original post by Glutamic Acid)
After the first integral you'll get an additive constant, so dv/dr = -kr/2 + c/r. So there's an extra c log r term in the answer.

I hate you

[sabby777]

this might not be an interesting maths problem, but I find it hard and would appreciate a step by step guide as to how to approach and solve this problem

so it's simultaneous equations, -

x^2 + 4y^2 = 10
2y+3x =10

[boromir9111]

(Original post by sabby777)
this might not be an interesting maths problem, but I find it hard and would appreciate a step by step guide as to how to approach and solve this problem

so it's simultaneous equations, -

x^2 + 4y^2 = 10
2y+3x =10

Post your homework in the maths forum, not here!

[meatball893]

(Original post by sabby777)
this might not be an interesting maths problem, but I find it hard and would appreciate a step by step guide as to how to approach and solve this problem

so it's simultaneous equations, -

x^2 + 4y^2 = 10
2y+3x =10

First of all, I'm sorry for the neg that I suspect some people will give you. However, this really ought to be in a separate thread, and not here.

Now, your question. Rearrange the second eqn to get y in terms of x, sub that into the first eqn, solve for y, sub into the 2nd eqn and solve for x.

If there are still some problems, I would encourage you to make a new thread, and feel free to quote me. (Since you're quite new, this can be done by pasting [quote=meatball893]x[/quote] into your post.)

[LStudent]

Hey guys i'm putting up my pure maths paper that i wrote today. I've put up 3 questions so far and will put the rest up tomorrow. For any of you revising C1-C4 do try the questions. The board is different from what you normally know but the content should be the same. Good luck.
http://www.thestudentroom.co.uk/show....php?t=1635035

[am05317z]

Hi guys ok I wonder if you can help me...Im currently revising for D1 edexcel maths....im trying to check my past paper and have got the mark scheme but it hasn't helped as I need to actually see a diagram...its Q8d in the paper I have attached...mark scheme just says see overlay.....would be great if someone could help me by drawing a diagram or something to check to see if i have it right or even tell me!!!!! Thanks any help appreciated!!

[anshul95]

(Original post by am05317z)
Hi guys ok I wonder if you can help me...Im currently revising for D1 edexcel maths....im trying to check my past paper and have got the mark scheme but it hasn't helped as I need to actually see a diagram...its Q8d in the paper I have attached...mark scheme just says see overlay.....would be great if someone could help me by drawing a diagram or something to check to see if i have it right or even tell me!!!!! Thanks any help appreciated!!

you need to post this in a new thread in the main maths help section.

[Oh I Really Don't Care]

What is everybody's philosophy of maths?

[boromir9111]

(Original post by DeanK22)
What is everybody's philosophy of maths?

Provides better understanding of the environment around you, not always relating to maths......critical thinking and as a result, copious amounts of opinions in all affairs......

[SimonM]

(Original post by DeanK22)
What is everybody's philosophy of maths?

Probably a Platonist if pushed, but the amount I care varies with how long it has been since I've read a philosophy book.

[around]

(Original post by DeanK22)
What is everybody's philosophy of maths?

i like playing games

[Zhen Lin]

(Original post by DeanK22)
What is everybody's philosophy of maths?

Probably some kind of Platonist. Maybe. But also relativist, so maybe not. I need to read more about the philosophy of mathematics.

[kfkle]

I like to think that CH is either true or false. I suppose that makes me a Platonist.

[Dadeyemi]

(Original post by DeanK22)
What is everybody's philosophy of maths?

http://www.timecube.com/

[Zhen Lin]

Fun fact: Every continuous real-valued function on can be uniformly approximated by polynomials with integer coefficients.

Exercise: Start by showing that the constant function may be so approximated. Then show that every real number may be so approximated.

[kfkle]

Some useful inequalities: http://www.lkozma.net/inequalities_cheat_sheet/

[ZeedoZee]

(Original post by The Muon)
A little one which isn't massively mathematical but it quite nice.

You travel from A to B at a speed of 30m/s and then back at a different speed. What speed should you travel back if you wish the average speed of the whole journey to be 60m/s?

I heard it in the pub the other night and so I hope that I got the numbers right

Would it not depend on the distance between A and B?

[Slumpy]

(Original post by ZeedoZee)
Would it not depend on the distance between A and B?

No.

[ZeedoZee]

(Original post by Slumpy)
No.

Ok I'm stumped. Give me a hint, how to approach the question and I'll try from there.

[Slumpy]

(Original post by ZeedoZee)
Ok I'm stumped. Give me a hint, how to approach the question and I'll try from there.

Let the distance A to B be d. Work out the time it would take to get an average speed of the speed you want in terms of d. Then compare that to how much time you've already taken in the case given, and you'll spot something.