« previous next »
Pages: [1]   Go Down

Author Topic: further math question...  (Read 1019 times)

Offline crucio

  • Newbie
  • *
  • Posts: 32
  • Reputation: 34
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  ::)
Logged

Offline astarmathsandphysics

  • SF Overlord
  • *********
  • Posts: 11271
  • Reputation: 65534
  • Gender: Male
  • Free the exam papers!
Re: further math question...
« Reply #1 on: October 22, 2009, 07:02:48 pm »
Will answer when i get home
Logged

Offline astarmathsandphysics

  • SF Overlord
  • *********
  • Posts: 11271
  • Reputation: 65534
  • Gender: Male
  • Free the exam papers!
Re: further math question...
« Reply #2 on: October 23, 2009, 10:15:34 am »
Quite a tricky question. Am doing it now.
Logged

Offline astarmathsandphysics

  • SF Overlord
  • *********
  • Posts: 11271
  • Reputation: 65534
  • Gender: Male
  • Free the exam papers!
Re: further math question...
« Reply #3 on: October 23, 2009, 11:02:52 am »
ttook an hour to do.
Logged

Offline Ghost Of Highbury

  • O_o_O lala!
  • SF Farseer
  • *******
  • Posts: 4096
  • Reputation: 41428
  • Gender: Male
  • Namaskaram!
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..!!
Logged
divine intervention!

Offline astarmathsandphysics

  • SF Overlord
  • *********
  • Posts: 11271
  • Reputation: 65534
  • Gender: Male
  • Free the exam papers!
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.
Logged

Offline crucio

  • Newbie
  • *
  • Posts: 32
  • Reputation: 34
Re: further math question...
« Reply #6 on: October 25, 2009, 04:01:06 pm »
thank you very much sir! ;D
Logged
Pages: [1]   Go Up
« previous next »