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Math Help - Problem with this Integration

  1. #1
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    Exclamation Problem with this Integration

    Hello there!

    I need help on solving the following equation.

    ∫ (π+t) cos (nt) dt + ∫ (π-t) cos (nt) dt


    I don't know if its clear but its like this "Integral of [(pi + t) into cos (nt)] dt + integral of [(pi - t) into cos (nt)] dt."



    I don't know how to continue after I expand each!!!




    Any help is much appreciated.



    Thanks,



    atwinix
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  2. #2
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    Hello, atwinix!

    Could you restate the problem?
    . . Your writing raises many questions.


    I need help on solving the following equation. . . . . Equation?

    ∫ (π+t) cos (nt) dt + ∫ (π-t) cos (nt) dt


    I don't know if it's clear but its like this:
    "Integral of [(pi + t) into cos (nt)] dt + integral of [(pi - t) into cos (nt)] dt."

    What does "into" mean?

    If the problem is: . \int(\pi + t)(\cos(nt)\,dt + \int(\pi - t)\cos(nt)\,dt
    . . why not make one integral?

    . . \int\bigg[\pi\cos(nt) + t\cos(nt) + \pi\cos(nt) - t\cos(nt)\bigg]\,dt \;=\;2\pi\int\cos(nt)\,dt<br /> <br />

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  3. #3
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    "into" means "multiply by."

    The problem is exactly just as you stated, Soroban.

    But what do I do if the limits on each part is different. Say from -pi < t < 0 for the first part and 0 < t < pi for the second part!!

    This integration has to do with a Fourier Series question, which you can check out below.

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  4. #4
    Grand Panjandrum
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    This has been dealt with in the other thread.

    RonL
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