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Math Help - I get a similar answer for this integral

  1. #1
    s3a
    s3a is offline
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    I get a similar answer for this integral

    I am trying to solve this integral:
    http://www.wolframalpha.com/input/?i=integral+(sin(4x))^2+*+(cos(4x))^2

    and I was just wondering what I am doing wrong (my work is attached).

    Any input would be greatly appreciated!
    Thanks in advance!
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  2. #2
    Ted
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    Quote Originally Posted by s3a View Post
    I am trying to solve this integral:
    http://www.wolframalpha.com/input/?i=integral+(sin(4x))^2+*+(cos(4x))^2

    and I was just wondering what I am doing wrong (my work is attached).

    Any input would be greatly appreciated!
    Thanks in advance!
    Hello,
    You did a substitution then you ignore it.
    you have mistake in the third line. The denominator should be 4 not 2.
    And you forgot the dx twice.
    Its better to evaluate by the substitution w=4x, which will make it:
    \int_0^{32} sin^2(w) cos^2(w) = ...
    Try it again.
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