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    Hi Mathematicians I need some help integrating this. It does not have any limits. The equation is cos(3x-1) how can I integrate this. I'm guessing that you should use substitution. Thank you in advance. =)
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    (Original post by WorkHardNow)
    Hi Mathematicians I need some help integrating this. It does not have any limits. The equation is cos(3x-1) how can I integrate this. I'm guessing that you should use substitution. Thank you in advance. =)
    No need to substitute

    I assume that you know the integral of Cosx

    Try differentiating Sin(3x-1) and see what that looks like
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    (Original post by TenOfThem)
    No need to substitute

    I assume that you know the integral of Cosx

    Try differentiating Sin(3x-1) and see what that looks like
    1/3cos(3x-1)+c
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    (Original post by WorkHardNow)
    1/3cos(3x-1)
    No, that is the integral


    But now I am confused ... given that you can integrate sin(3x-1) I do not know why you cannot do the original question
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    (Original post by TenOfThem)
    No, that is the integral


    But now I am confused ... given that you can integrate sin(3x-1) I do not know why you cannot do the original question
    I don't know I am confused because my teacher said its substitution and I'm just getting the wrong answer.
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    (Original post by WorkHardNow)
    I don't know I am confused because my teacher said its substitution and I'm just getting the wrong answer.
    Ok well, use u=3x-1

    That will work but will take longer
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    d/dx (sin(3x -1)) = 3cos(3x - 1)

    so the integration of cos(3x -1) is (1/3)(sin(3x -1)
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    do the original and differentiate it, the orignial is sin(3x-1)
    dy/dx= 3cos(3x-1)

    but cos(3x-1) is missing the multiple of 3 therefore your original should be 1/3sin(3x-1) to get rid of the multiple of 3 you would have got from differentiating sin(3x-1)

    therefore cos(3x-1) intergrated is 1/3sin(3x-1)
 
 
 
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