A community for students.
Here's the question you clicked on:
 0 viewing
husbishag
 2 years ago
Compute ∫ x cos(x)dx.
Would we use Integration by Parts and compute this as  sin(x) = Cos(x) + C ????
husbishag
 2 years ago
Compute ∫ x cos(x)dx. Would we use Integration by Parts and compute this as  sin(x) = Cos(x) + C ????

This Question is Closed

husbishag
 2 years ago
Best ResponseYou've already chosen the best response.0I wrote that incorrectly. sin(x)+ cos(x) + C

TuringTest
 2 years ago
Best ResponseYou've already chosen the best response.0close, but not quite

TuringTest
 2 years ago
Best ResponseYou've already chosen the best response.0\[u=x\]\[dv=\cos xdx\]\[\int udv=uv\int vdu\]look carefully and you should be able to see you dropped an x in there

husbishag
 2 years ago
Best ResponseYou've already chosen the best response.0@TuringTest , I'm a little confused on your explanation, where have I dropped an x?

TuringTest
 2 years ago
Best ResponseYou've already chosen the best response.0u=x, and there is a u on the right of the formula. There should be an x where the u is...

husbishag
 2 years ago
Best ResponseYou've already chosen the best response.0@TuringTest I think I see. So, it would be sin(x) + x cos(x) + C

TuringTest
 2 years ago
Best ResponseYou've already chosen the best response.0what you have above is\[vdu\int uv\]careful, identify your v and u, dv and du!

TuringTest
 2 years ago
Best ResponseYou've already chosen the best response.0\[u=x\implies du=dx\]\[dv=\cos xdx\implies v=\sin x\]\[\int udv=uv\int vdu\]slowly and carefully plug in each for u, v, and du

husbishag
 2 years ago
Best ResponseYou've already chosen the best response.0@TuringTest Thank you for your patience with me. Would it be x sin x + cos x + C?

TuringTest
 2 years ago
Best ResponseYou've already chosen the best response.0\[u=x\implies du=dx\]\[dv=\cos xdx\implies v=\sin x\]\[\int udv=uv\int vdu\]\[\int x\cos xdx=x(\sin x)\int(\sin x)dx=x\sin x+\int\sin xdx\]

TuringTest
 2 years ago
Best ResponseYou've already chosen the best response.0crap I made up a negative sign

RadEn
 2 years ago
Best ResponseYou've already chosen the best response.1int cosx = sinx not sinx

TuringTest
 2 years ago
Best ResponseYou've already chosen the best response.0\[u=x\implies du=dx\]\[dv=\cos xdx\implies v=\sin x\]\[\int udv=uv\int vdu\]\[\int x\cos xdx=x(\sin x)\int(\sin x)dx=x\sin x+\int\sin xdx\]yeah you were right, my bad :P

husbishag
 2 years ago
Best ResponseYou've already chosen the best response.0If only one day I could understand math that way both of you do... thanks for your help!
Ask your own question
Sign UpFind more explanations on OpenStudy
Your question is ready. Sign up for free to start getting answers.
spraguer
(Moderator)
5
→ View Detailed Profile
is replying to Can someone tell me what button the professor is hitting...
23
 Teamwork 19 Teammate
 Problem Solving 19 Hero
 Engagement 19 Mad Hatter
 You have blocked this person.
 ✔ You're a fan Checking fan status...
Thanks for being so helpful in mathematics. If you are getting quality help, make sure you spread the word about OpenStudy.