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#401 Re: Dark Discussions at Cafe Infinity » Problems with discipline » 2014-05-24 13:19:56

Sorry, I thought you meant no precalculus at all.

Please check abebooks.com and search precalculus sullivan exactly. I can see a $4 copy.

#402 Re: Dark Discussions at Cafe Infinity » Problems with discipline » 2014-05-24 13:10:50

To be brutally honest, forget the idea of a math major. You need precalculus. You can get the books for 2 Euros on abebooks.com.

#403 Re: Puzzles and Games » Cube it! » 2014-05-24 12:45:44

Henceforth let's write the number we are cubing.

27^3 = 19683

#404 Re: Introductions » Let us welcome zetafunc. » 2014-05-24 12:36:57

I didn't care about moving. If I was rejected from MIT, I would have gone to UCl or Oxford most likely. But I am not sure what I was exactly thinking at that time - maybe ICL was one of my choices too?

#405 Re: Dark Discussions at Cafe Infinity » Problems with discipline » 2014-05-24 12:35:15

Please tell me why you are wasting your time on English. Your English seems fine too me, unless you want to major in English literature.

Please tell me why you are wasting your time on Physics. You cannot do Physics right now. You need more mathematics (ideally calculus, but good algebra and trigonometry/precalculus at least). 

Geometry by Lang will not take you two months - I guarantee that - unless you have severe discipline issues.

You did not answer the two questions I asked at the end of my last post.

Sullivan has a lot of Precalculus books. I meant http://www.amazon.com/Precalculus-9th-M … 0321716833 or any other edition (buy it from abebooks.com).

I said Jacobs' Geometry book, not Sullivan's. You do not need it, but it is better if you look at it as it is a bit easier than Lang and will help you (and it is available online for free).

#406 Re: Dark Discussions at Cafe Infinity » Problems with discipline » 2014-05-24 11:34:24

PatternMan wrote:
ShivamS wrote:

-you are not used to studying intensively (this is very common and I think it is one of your problems - you obviously haven't studied so hard in the past so it will take time to get used to it, but it will happen)

No I'm not. How do I get used to it?

Start small (e.g. 1 hour per day for 2 days, then 3 hours per day etc), build your motivation etc.

PatternMan wrote:
ShivamS wrote:

-you want to solve math problems but don't want to learn the material for it (this applies to you but the biggest problem regarding this is that you decided not to do any problems. I suggest you learn math and do problems alongside it, even if it's only a few problems to save time)

I have been mainly focusing on the theory. In the mainstream books they don't define terms like:
line segment
ray
axiom/postulate
plane
theorom
proof

You just get a geometric sense of what they mean when they say these things in regular books. Actualy they don't use many of the terms and you don't really need to know what they mean. I really just remember the procedures and do them. I don't even really know the rules in of themselves. I just pick them up from doing the problems and seeing what works.

I am making sure I understand what the definitions in this book by thinking which concepts they stand on, and of non examples. Lang's Geometry builds up everything from scratch so it's fun. You get the basic definitions, basic axioms, then construct shapes, then do some problems, then some proofs. I already knew the formula and theoroms in the book but I did not understand it much. I didn't know the definitions, axioms, notation, or how anything was derived. Or even that this was Euclidian geometry and that there are others. It is tedious to focus on these definitions and practice memorizing them but I know it's for the best.

You are beating a dead horse. Those ridiculous books are behind you - now you have access to great books written by great people.

PatternMan wrote:
ShivamS wrote:

-you want to learn higher mathematics like calculus and are not interested in the prerequisites (this happened to me but after a while I enjoyed learning it)

It's not that I don't want to learn the pre-requisites, it's just the more advanced topics seem more exciting. I still really need to brush up on number theory more than anything.

To be honest you should not be thinking about number theory right now. Most of number theory requires algebra anyway.

PatternMan wrote:

I'm going to alternate between the fun and more tedious parts. Rewarding myself with some break and problems after studying the concepts should do the trick. Hopefully i'll end up doing it longer. The problem is I'm teaching myself some other things too which are all memory based since I don't really have the equipment to do them.

Good!

PatternMan wrote:

The problem is I'm teaching myself some other things too which are all memory based since I don't really have the equipment to do them.

Which things?

I have two final questions. Are you planning to go through each one of the following books page by page?
Basic Mathematics by Lang
Elementary and Intermediate Algebra by Sullivan (this is one book - there are two separate books as well but get the book with both of them)
Precalculus by Sullivan
Geometry by Jacobs (1st or 2nd edition)

Those books are the bare minimum you need if you want to go into a mathematics program and succeed .

Second question. Do you think you will be able to go through
Geometry by Lang
Algebra by Gelfand
along with the 4 books above? If yes, then excellent. If not, then make sure you go through those four books at least.

#407 Re: Introductions » Let us welcome zetafunc. » 2014-05-24 07:51:04

Hi zetafunc;

I visited the university you go to about one to two years ago and I probably would have been there if I was rejected from my current university (or Oxford, but I hadn't decided)!

#408 Re: Dark Discussions at Cafe Infinity » Happy Birthday, Alokananda! » 2014-05-24 06:33:21

bobbym wrote:

Good night

Technically it is the afternoon.

#409 Re: Dark Discussions at Cafe Infinity » Happy Birthday, Alokananda! » 2014-05-24 06:20:40

Well, I think it's time for me to go to sleep at 2 in the afternoon. I will try to solve it later.

#413 Re: Dark Discussions at Cafe Infinity » Happy Birthday, Alokananda! » 2014-05-24 06:07:49

bobbym wrote:

how do I compute the last three digits of 2014C1+2013C3+2014C5+...+2014C2013 by hand?

Your second term is 2013C3, that can not be right.

Why? It alternates between 2014 and 2013. I will write it out better:
2014C1+2013C3+2014C5+2013C7...+2014C2013

#416 Re: Science HQ » work and energy problem » 2014-05-24 04:46:48

This is the diagram f-d%3A8292b2c57c699bb6250a8bcc311533b0d742874a453808f1f37f68e1%2BIMAGE%2BIMAGE.1

Let the sphere move towards left with an acceleration ‘a’ and let us examine the particle’s motion from the sphere, i.e. assuming the sphere at rest.
Let m = mass of the particle

Now, the particle is moving in a circle on the surface of the sphere.

The free body diagram of the particle is f-d%3A166c2f5e831224eaa8aa276109021b41b492d2fa9be41037c3a9cdfa%2BIMAGE%2BIMAGE.1

When the particle has slid through an angle θ, let its velocity be ‘v’.

Tangential acceleration = mdv/dt = macosθ + mgsinθ

We know that v = Rdθ/dt

Therefore, mvdv/dt = macosθ(Rdθ/dt) + mgsinθ(Rdθ/dt)

or mvdv = maRcosθdθ + mgRsinθdθ

Integrating both sides;

v^2 /2 = aRsinθ – gRcosθ+ c

Given that the particle starts from rest, i.e. v = 0 at θ = 0

Therefore, c = +gR

Hence, v^2 = 2aRsinθ – 2gRcosθ+ 2gR

or v = [2R(asinθ – gcosθ +g)]^½

#417 Re: Dark Discussions at Cafe Infinity » Happy Birthday, Alokananda! » 2014-05-24 04:04:05

That is her? I forget that she was her.

Alokasarkar S. wrote:

I am Alokananda Sarkar.

Well, she doesn't post much.

#419 Re: Maths Is Fun - Suggestions and Comments » Is your approximately showing? » 2014-05-24 04:00:49

gAr tried it in chrome and it didn't work.

Edit: It doesn't work in my browser now either. I am seeing the same three characters you all are.

#420 Re: Dark Discussions at Cafe Infinity » Happy Birthday, Alokananda! » 2014-05-24 03:59:47

Happy birthday!

You should have her join the forum.

#421 Re: Science HQ » work and energy problem » 2014-05-24 02:55:32

I would solve it but since I am on a phone and you want a quick answer, google the problem. You will find many full solutions.

#422 Re: Maths Is Fun - Suggestions and Comments » Is your approximately showing? » 2014-05-24 01:21:11

The approximately sign wasn't showing for me before likely because I was using my phone. On my computer it works fine.

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