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# Math Integration Help C3/C4 watch

1. 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. =)
2. (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
3. (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
4. (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
5. (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.
6. (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
7. d/dx (sin(3x -1)) = 3cos(3x - 1)

so the integration of cos(3x -1) is (1/3)(sin(3x -1)
8. 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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