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Antiderivative of 1.4x*cos(x^1.9)

  • Thread starter momogiri
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52
0
Question

f'(x) = 1.4x*cos(x^1.9)
Find f(x)

Attempt
Ok, first of all, I'm really bad at Calculus, so bear with me >__<
I figured to find the antiderivative of the thing is equivalent to
[tex]\int\left1.4x*cos\leftx^{1.9}\right\right)dx[/tex]

I've tried simple substitution (u = x^1.9) and that obviously doesn't work, and I tried integration by parts, but I don't think it's working
If I had dv = cos(x^1.9)dx
I'm unsure if I can find v when x is x^1.9

Help will be appreciated! Thanks!
 
Last edited:

Answers and Replies

6
0
Question

f'(x) = 1.4x*cos(x^1.9)
Find f(x)

Attempt
Ok, first of all, I'm really bad at Calculus, so bear with me >__<
I figured to find the antiderivative of the thing is equivalent to
[tex]\int\left1.4x*cos\leftx^{1.9}\right\right)dx[/tex]

I've tried simple substitution (u = x^1.9) and that obviously doesn't work, and I tried integration by parts, but I don't think it's working
If I had dv = cos(x^1.9)dx
I'm unsure if I can find v when x is x^1.9

Help will be appreciated! Thanks!
Your doing the math lab arn't you? I have the same problem except my f'(x) = 1.7x*sin(x^1.8)
 
1,750
1
You have two different Integrals ... which is it?

[tex]\int1.4x\cos{x^{1.9}}dx[/tex]

or

[tex]\int1.4x\cos^{1.9}xdx[/tex]

Does the power belong to cosine or the variable x?
 
827
13
Have you tried Taylor expansion? That's all I can think of now.
 
458
0
If you're doing the mathlab for a UBC math course *cough*, then use the spreadsheet.
 

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