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Math Help - Computer Algebra System that Can Integrate this Function

  1. #1
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    Computer Algebra System that Can Integrate this Function

    For some reason, wolfram alpha does not seem to understand integration.

    http://www.wolframalpha.com/input/?i=(1%2FL)*((integrate+(a_1*x^2%2Ba_2*x%2Ba_3)*(co s(n*pi*x%2FL)+from+-L+to+0)%2B(integrate+(b_1*x^2%2Bb_2*x%2Bb_3)*(cos( n*pi*x%2FL)++from+0+to+L))


    Is there a computer algebra system that can integrate
    (1/L)*((integrate (a_1*x^2+a_2*x+a_3)*(cos(n*pi*x/L) from -L to 0)+(integrate (b_1*x^2+b_2*x+b_3)*(cos(n*pi*x/L) from 0 to L))
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  2. #2
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    Re: Computer Algebra System that Can Integrate this Function

    You will probably be able to do it with Maple. Can you LaTeX (LaTeX - Wikipedia, the free encyclopedia) the integrals that you want?

    My guess is

    \frac{1}{L}\left( \int_{-L}^0\left( a_{1}x^2+a_{2}x+a_{3}\right) \cos\left( \frac{n \pi x}{L}\right)dx +\int_{0}^{L}\left(b_{1}x^2+b_{2}x+b_{3} \right)\cos\left( \frac{n \pi x}{L}\right)dx  \right)

    To do that integral I will first re-scale x to u_{n}=\frac{n \pi x}{L} and then integrate by parts two times in order to lower the grade of the polynomial. A little of brute force but it works just fine.
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  3. #3
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    Re: Computer Algebra System that Can Integrate this Function

    Quote Originally Posted by Philly2034 View Post
    For some reason, wolfram alpha does not seem to understand integration.

    http://www.wolframalpha.com/input/?i=(1%2FL)*((integrate+(a_1*x^2%2Ba_2*x%2Ba_3)*(co s(n*pi*x%2FL)+from+-L+to+0)%2B(integrate+(b_1*x^2%2Bb_2*x%2Bb_3)*(cos( n*pi*x%2FL)++from+0+to+L))


    Is there a computer algebra system that can integrate
    (1/L)*((integrate (a_1*x^2+a_2*x+a_3)*(cos(n*pi*x/L) from -L to 0)+(integrate (b_1*x^2+b_2*x+b_3)*(cos(n*pi*x/L) from 0 to L))
    Why not try it with properly matched parentheses, also break it down into smaller parts.

    .
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