Math Is Fun Forum

Balkees

Member

Registered: 2010-10-09

Posts: 2

Need Urgent Help .... I should submit it after 3-Hours

Evaluate

[math][∫_(-∞)^∞▒〖( x/√2π   e^(- ( x-2 )^2/2)   dx)〗]

bobbym

bumpkin

From: Bumpkinland

Registered: 2009-04-12

Posts: 109,606

Re: Need Urgent Help .... I should submit it after 3-Hours

Hi Balkees;

I am unable to understand your latex. So I have to guess at it,

Maybe it is this?

Off hand I would say the x in the numerator, should not be there.

Do you see why?

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In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
Always satisfy the Prime Directive of getting the right answer above all else.

Bob

Administrator

Registered: 2010-06-20

Posts: 10,583

Re: Need Urgent Help .... I should submit it after 3-Hours

Hi Balkees

Did you mean

Here's the code I used to get this without the leading 'brackets math'

\int^\infty_{-\infty} \frac{x}{\sqrt{2n}} e^{- ( x-2 )^2/2}     [/math]

Hi bobbym

You got there while I was still constructing my code!

Bob

Last edited by Bob (2010-10-09 22:33:38)

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Children are not defined by school ...........The Fonz
You cannot teach a man anything;  you can only help him find it within himself..........Galileo Galilei
Sometimes I deliberately make mistakes, just to test you!  …………….Bob

bobbym

bumpkin

From: Bumpkinland

Registered: 2009-04-12

Posts: 109,606

Re: Need Urgent Help .... I should submit it after 3-Hours

Hi bob bundy;

His latex if that is what it is, is incomprehensible. Think that those are reasonable guesses but he might have a mistake with the x also.

---

In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
Always satisfy the Prime Directive of getting the right answer above all else.

Balkees

Member

Registered: 2010-10-09

Posts: 2

Re: Need Urgent Help .... I should submit it after 3-Hours

Hi bobbym,

Thanks alot for your response.
please, how did you evaluate it to get the result 2  ?

bobbym

bumpkin

From: Bumpkinland

Registered: 2009-04-12

Posts: 109,606

Re: Need Urgent Help .... I should submit it after 3-Hours

Hi Balkees;

That is my point. Are you sure you have copied the problem correctly?

See the x in the numerator with the box around it? With that x there I do not recognize the integral.
I had to use a computer. Without the x it is easy! When I say easy I do not mean some silly substitution.
I mean there is a precise mathematical reason why the integral can be evaluated by sight!

If this is a school problem I am willing to bet my favorite mustard that x does not belong there!

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In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
Always satisfy the Prime Directive of getting the right answer above all else.