Integration problem Watch

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Womble548
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#1
Report Thread starter 14 years ago
#1
Can somone help me integrate this:
INT 2e^(3x^2)

Parts isnt working and neither is substitution. Am I doing something wrong?
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Gauss
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Report 14 years ago
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(Original post by Womble548)
Can somone help me integrate this:
INT 2e^(3x^2)

Parts isnt working and neither is substitution. Am I doing something wrong?
I'll assume the limits are between -infinity and infinity.

Use the substitution x = z/root(3)i
=> z = root(3)ix
=> z^2 = -3x^2
=> -z^2 = 3x^2

Also,

dz/dx = root(3)i
=> "dx = dz/root(3)i"

So integral becomes

INT (2/root(3)i)*exp(-z^2) dz

Using the fact that INT e^(-z^2) [-infinity...infinity] = root(pi), then we can deduce

INT (2/root(3)i)*exp(-z^2) dz [-infinity...infinity] = (2/root(3)i)*root(pi) = (2/3).i.[root(3pi)]

Euclid.
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Womble548
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#3
Report Thread starter 14 years ago
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Ouch, thanks for the reply. Must have done something wrong in the question as that is definately not P4-5 stuff! (Well not without being told the substitution!)
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