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Math Help - Please Check: Itergrate by Substitution

  1. #1
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    Please Check: Itergrate by Substitution

    Q. Use as substitution to find:

    {Intergration symbol} sin(3 + 2x) . dx

    if U = 2x + 3 then du = 2. dx

    = 1/2 {Intergration symbol} sin (U) . du

    = - cos (U) / 2 + c

    = - 1/2 . cos (2x + 3) + c


    Not sure the method is correct?
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  2. #2
    MHF Contributor harish21's Avatar
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    Quote Originally Posted by Parton-Bill View Post
    Q. Use as substitution to find:

    {Intergration symbol} sin(3 + 2x) . dx

    if U = 2x + 3 then du = 2. dx

    = 1/2 {Intergration symbol} sin (U) . du

    = - cos (U) / 2 + c

    = - 1/2 . cos (2x + 3) + c


    Not sure the method is correct?
    Perfectly done. You are correct.
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  3. #3
    Master Of Puppets
    pickslides's Avatar
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    Quote Originally Posted by Parton-Bill View Post
    Q. Use as substitution to find:

    {Intergration symbol} sin(3 + 2x) . dx

    if U = 2x + 3 then du = 2. dx

    = 1/2 {Intergration symbol} sin (U) . du

    = - cos (U) / 2 + c

    = - 1/2 . cos (2x + 3) + c


    Not sure the method is correct?
    Answer is good.

    Best way to check is find \frac{d}{dx}\left(\frac{- 1}{2} \cos (2x + 3) + C\right)
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  4. #4
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    thank you very much guys, I really struggle with my confidence in regards to calculus, so feedback, especially encourageing feedback is an essentail part of building my confidence.

    thanks again
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