Author Topic: Improper integral  (Read 1300 times)

Offline @d!_†oX!©

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Improper integral
« on: August 12, 2010, 02:17:27 pm »
Probably a very easy question..but can anyone please explain what to do if the limits given to us for integration have either inifinite or -ve infinite??
Pure maths 1
Thanks in advance..i have an exam tom..please help if you can
AAL IZZ WELL!!! ;)

Alpha

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Re: Improper integral
« Reply #1 on: August 12, 2010, 02:41:16 pm »
Hm, you have to analyse what happens to the value of your integrated expression when the value of x is increasing.


Offline Saladin

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Re: Improper integral
« Reply #2 on: August 12, 2010, 02:44:02 pm »
Please give me a question as an example.

Offline @d!_†oX!©

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Re: Improper integral
« Reply #3 on: August 12, 2010, 03:10:01 pm »
Please give me a question as an example.

here you go..
AAL IZZ WELL!!! ;)

Offline cooldude

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Re: Improper integral
« Reply #4 on: August 12, 2010, 03:14:19 pm »
here you go..

integrate the integrand first, we get (x^-1)/-1=-x^-1=-1/x
the limits are infinity and 1, when x tends to infinity y tends to 0, i.e. the integral tends to 0, therefore we get 0-(-1/1)=1

Offline cooldude

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Re: Improper integral
« Reply #5 on: August 12, 2010, 03:15:36 pm »
oh yeah and just read it from the book, ull get it, and when the limits are infinity its an infinite integral
« Last Edit: August 12, 2010, 03:20:11 pm by cooldude »

Offline Saladin

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Re: Improper integral
« Reply #6 on: August 12, 2010, 05:59:44 pm »
Never tried one of these before.