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A tricky integration problem. Save me!

  1. Nov 4, 2004 #1
    I was asked to integrate( exp(-x) cos(x)) with respect to x with the limits x=0 and x= infinity.
    I calculated the indefinite integral to be 0.5 exp(-x) [sin(x)-cos(x)].

    I was stuck in the part where we apply limit x approaches infinity of sin(x) and cos x.

    Please help me out.

  2. jcsd
  3. Nov 4, 2004 #2


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    Homework Helper

    e^-x goes to zero at infinity, so the other terms arent important, as long as theyre finite, which they clearly are.
  4. Nov 6, 2004 #3
    Thanks for your reply StatusX. I really appreciate it.
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