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Math Help - cos(sqrt x)

  1. #1
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    cos(sqrt x)

    HELLO,

    I d be grateful to anyone who solves the following, as I have been trying for ages but it is not working.

    Q/ solve by finding appropriate substitution and then integrate by parts:
    integral of cos(sqrt x).

    Thanks.
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  2. #2
    Grand Panjandrum
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    Quote Originally Posted by fadeer View Post
    HELLO,

    I d be grateful to anyone who solves the following, as I have been trying for ages but it is not working.

    Q/ solve by finding appropriate substitution and then integrate by parts:
    integral of cos(sqrt x).

    Thanks.
    What is wrong with u=\sqrt{x} , then integrate by parts

    CB
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  3. #3
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    I am sorry but could you make it a little clearer.
    Thanks.
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  4. #4
    Grand Panjandrum
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    Quote Originally Posted by fadeer View Post
    I am sorry but could you make it a little clearer.
    Thanks.
    If u=\sqrt{x} we have:

     <br />
\int \cos(\sqrt{x})\; dx=\int \cos(u) \frac{dx}{du}\;du=2 \int u\cos(u)\;du<br />

    and now you use integration by parts.

    (If you need more help WolframAlpha will give you a step by step explanation of the complete process)

    CB
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  5. #5
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    Thanks a lot bro,

    No need bcz I know to complete it.
    I was stuck with the substitution part.

    I appreciate ur help.
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