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**zetafunc.****Guest**

Suppose you had the integral

So now we let:

We have

and

Adding these two equations yields:

Thus,

**bobbym****Administrator**- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 84,759

Hi;

Yes, that is a very nice idea.

**In mathematics, you don't understand things. You just get used to them.I have the result, but I do not yet know how to get it.All physicists, and a good many quite respectable mathematicians are contemptuous about proof.**

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**zetafunc.****Guest**

Unfortunately it doesn't seem to work nearly as often as one would like!

**bobbym****Administrator**- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 84,759

It is a trick and as such you use it when you can.

**In mathematics, you don't understand things. You just get used to them.I have the result, but I do not yet know how to get it.All physicists, and a good many quite respectable mathematicians are contemptuous about proof.**

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**zetafunc.****Guest**

That's the thing when you learn a new trick... you want to use it on everything but really it will only work on a few problems.

**bobbym****Administrator**- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 84,759

I think it was Alan Turing along with Alonzo Church that proved a long time ago that for an infinite number of problems you will require an infinite number of methods.

My favorite trick involved an integral and a recurrence. Not so difficult but when I first so it I was amazed.

**In mathematics, you don't understand things. You just get used to them.I have the result, but I do not yet know how to get it.All physicists, and a good many quite respectable mathematicians are contemptuous about proof.**

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**zetafunc.****Guest**

What trick is that?

**bobbym****Administrator**- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 84,759

Supposing you want to evaluate this integral:

you might first embed it into a whole family of integrals called y.

you could now work it like this.

Factor:

Now you have solved for the family y in terms of a useful recurrence relation.

I have the result, but I do not yet know how to get it.

All physicists, and a good many quite respectable mathematicians are contemptuous about proof.

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**zetafunc.****Guest**

That is impressive. A question like that came up in my STEP III exam -- except we had a trig version.

**bobbym****Administrator**- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 84,759

When I first saw it I loved it and tried to find more of them. But they are few and far between.

I have the result, but I do not yet know how to get it.

All physicists, and a good many quite respectable mathematicians are contemptuous about proof.

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**zetafunc.****Guest**

Do you use a CAS for almost every integration problem you encounter?

**bobbym****Administrator**- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 84,759

If I am doing an integration problem where there is something I need to learn how to do then I do it by hand no matter how long it takes. If someone is asking a question I will do it by hand for them and then use the CAS to check.

But if I am doing another type of problem and an integral or a sum or a limit crops up as a small part of the problem I do not let it take my concentration off the bigger problem. If you get caught up in the small details you can lose sight of what you originally were working on. I always use a CAS there.

I have the result, but I do not yet know how to get it.

All physicists, and a good many quite respectable mathematicians are contemptuous about proof.

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**zetafunc.****Guest**

I understand what you mean. And there are also lots of problems that CAS's give odd-looking answers for, and many integrals that they cannot do (yet can be done on paper). A lot of integrals in STEP were like that.

**bobbym****Administrator**- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 84,759

CAS's give odd-looking answers for, and many integrals that they cannot do

A CAS does not mean you shut your brain off. Sometimes you have to help him along. With practice you will find that the number of integrals, sums, DE's , limits and simplifications you can do will increase by a factor of 10.

I have the result, but I do not yet know how to get it.

All physicists, and a good many quite respectable mathematicians are contemptuous about proof.

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**zetafunc.****Guest**

I was just looking at my UCL course and it appears that you can't go down the computational route without sacrificing the pure maths route... I can either fit into one category or the other!

**bobbym****Administrator**- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 84,759

Who ever said you needed UCL to teach you computational math or any other type. They are mostly just good for supplying you with credentials and reputation. Like all the other things in life you will have to teach yourself.

I have the result, but I do not yet know how to get it.

All physicists, and a good many quite respectable mathematicians are contemptuous about proof.

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**zetafunc.****Guest**

OK, but the problem is that if I do not take some computational modules then I won't be allowed to take other ones the next year (they claim I would not have the pre-requisite knowledge).

I like to self-teach, but often when I do that, there are lots of holes in my knowledge.

**bobbym****Administrator**- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 84,759

They are a product of self understanding. If you are forced down that road and that just might be the case you will have the satisfaction of knowing you are unique. If a hundred of them come out of some university they may not be fragmented but they are also bereft of imagination. All one hundred will be mirror images, all exactly alike.

I have the result, but I do not yet know how to get it.

All physicists, and a good many quite respectable mathematicians are contemptuous about proof.

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**zetafunc.****Guest**

Yes, I do not want to be like that. But, hopefully my passion will never dwindle.

**bobbym****Administrator**- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 84,759

Then if they will not teach then you will still find a way to learn.

I have the result, but I do not yet know how to get it.

All physicists, and a good many quite respectable mathematicians are contemptuous about proof.

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**zetafunc.****Guest**

Hopefully the quality of teaching won't affect it too much.

**bobbym****Administrator**- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 84,759

If you can decide what you most likely want to be then choose the one that fits that best.

I have the result, but I do not yet know how to get it.

All physicists, and a good many quite respectable mathematicians are contemptuous about proof.

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**zetafunc.****Guest**

What do you mean? You mean, as a career?

**bobbym****Administrator**- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 84,759

Not necessarily, although that would certainly be a way to decide. Even as a lifelong hobby.

I have the result, but I do not yet know how to get it.

All physicists, and a good many quite respectable mathematicians are contemptuous about proof.

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**zetafunc.****Guest**

Seems like life is just flying by...