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Author Topic: further math question...  (Read 1214 times)

Offline crucio

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further math question...
« on: October 22, 2009, 04:37:09 pm »
I_n = \displaystyle\int^1_0 x^n e^{-ax}\,dx \Rightarrow\alpha I_n =nI_{n-1} - e^{-\alpha}

find the Y coordinate of the centroid of the finite region bounded by the x-axis,
the line x = 1 and the curve y=xe^{-x}, giving your answers in terms of e.

ans: \dfrac{e^2 -5}{8e(e-2)}

dunno how 2 arrive at da correct ans, i took \alpha as 2 for I_2 but still im not gettin correct value...

ne help wud b highly appreciated...Thanks  ::)
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Offline astarmathsandphysics

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Re: further math question...
« Reply #1 on: October 22, 2009, 07:02:48 pm »
Will answer when i get home
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Offline astarmathsandphysics

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Re: further math question...
« Reply #2 on: October 23, 2009, 10:15:34 am »
Quite a tricky question. Am doing it now.
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Offline astarmathsandphysics

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Re: further math question...
« Reply #3 on: October 23, 2009, 11:02:52 am »
ttook an hour to do.
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Offline Ghost Of Highbury

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Re: further math question...
« Reply #4 on: October 23, 2009, 01:09:07 pm »
Quote from: astarmathsandphysics on October 23, 2009, 11:02:52 am
ttook an hour to do.

r u serious sir?

if so, man!!!....i'm gonna face some horrible time with further maths in A levels..

gonna prepare from the start..!!
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divine intervention!

Offline astarmathsandphysics

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Re: further math question...
« Reply #5 on: October 23, 2009, 01:51:05 pm »
Yes it was a quaestion full of tricky algebra. I couldn't read the pages I wrote cos of all the corrections I made.
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Offline crucio

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Re: further math question...
« Reply #6 on: October 25, 2009, 04:01:06 pm »
thank you very much sir! ;D
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