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#1 2013-05-20 16:43:24

{7/3}
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Continuous functions

I have been give a function f(x)=3x^3+x-2,how do i show it is a continuous function?

There are 10 kinds of people in the world,people who understand binary and people who don't.

#2 2013-05-20 20:03:23

bobbym

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Re: Continuous functions

Hi;

All polynomials are continuous.

You might try here and see if you like his proof:

http://www.proofwiki.org/wiki/Polynomial_is_Continuous

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.

#3 2013-05-20 20:28:07

{7/3}
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Re: Continuous functions

I'd love to go to that link but for some reason the link's words look weired and i can't read them.

There are 10 kinds of people in the world,people who understand binary and people who don't.

#4 2013-05-20 20:42:05

bobbym

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Re: Continuous functions

Hi;

Okay, I have a snapshot of it:

Let's see if these will suffice because they are simpler than epsilon delta type proofs.

I am assuming you are talking about continuity in R.

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.

#5 2013-05-20 21:43:08

{7/3}
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Re: Continuous functions

Thanks a lot bobbym

There are 10 kinds of people in the world,people who understand binary and people who don't.

#6 2013-05-20 21:47:48

bobbym

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Re: Continuous functions

Hi;

It is really going to depend on how far back they want you to go. If they will accept that any linear function ( ax + b ) is continuous then we are done with the above. If not, you may have to prove the theorem on linear functions first.

Also, somebody else might have a better 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.

#7 2013-05-20 22:23:29

{7/3}
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Re: Continuous functions

I know how to prove linear functions are continuous

There are 10 kinds of people in the world,people who understand binary and people who don't.

#8 2013-05-20 22:27:46

bobbym

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Re: Continuous functions

Hi;

Then I think we are done here...

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.

#9 2013-05-20 23:14:59

bob bundy
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Re: Continuous functions

hi {7/3}

in post 3 you  wrote:

I'd love to go to that link but for some reason the link's words look weired and i can't read them.

The maths appears to be in a Latex like code.  Maybe your browser isn't set to view it properly.  Try View Source.

And I found it took a while for all the code to be interpreted correctly.

Bob

You cannot teach a man anything;  you can only help him find it within himself..........Galileo Galilei

#10 2013-05-20 23:28:02

{7/3}
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Re: Continuous functions

Thanks for the advice,bob bundy,i will try it.

There are 10 kinds of people in the world,people who understand binary and people who don't.