Are These Indefinite Integral Solutions Correct?

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Homework Help Overview

The discussion revolves around verifying the correctness of indefinite integral solutions presented by the original poster, focusing on integration problems from a textbook. The subject area is calculus, specifically the evaluation of indefinite integrals.

Discussion Character

  • Exploratory, Assumption checking

Approaches and Questions Raised

  • The original poster seeks validation of their answers to several integration problems, expressing uncertainty about their correctness. Some participants question the appropriateness of the request for verification without a deeper inquiry into the underlying concepts.

Discussion Status

The discussion includes various responses, with some participants suggesting that simply checking answers may not align with the forum's purpose. However, there are also suggestions for tools and methods to verify the integrals, indicating a productive exchange of resources.

Contextual Notes

Participants note that the original poster's intent appears to be avoiding potential point deductions from their instructor, which raises questions about the motivations for seeking help in this context.

DMT
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Hey, I just need you guys to help verify that I got the correct answers on some of the even integration problems in my book. If one of them is incorrect, I'll post my work and hopefully can find out where I went wrong. Thanks!

1. \int xcos(x^{2})dx = \frac{1}{2} sin(x^{2}) +C

2. \int x^{2}cos(x)dx = x^{2}sinx + 2xcosx - 2sinx + C

3. \int x^{2}e^{-x}dx = -e^{-x}(x^{2} +2x + 2) + C

4. \int e^{x}sinxdx = \frac{1}{2}(-e^{x}cosx + e^{x}sinx) + C
 
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Hah! They are all right. Which probably suggests you are pretty good at what you are doing and don't really have a real "question". I'm not sure just checking homework answers is really what we're about here.
 
Dick said:
Hah! They are all right. Which probably suggests you are pretty good at what you are doing and don't really have a real "question". I'm not sure just checking homework answers is really what we're about here.

Ok, sorry! I just wanted to make sure they were correct before I turned it in so my instructor wouldn't take off points. I'll keep my posts to HW help from now on. Though, if one of the answers ended up being incorrect, the post would have turned into a homework help post right away ;)
 
http://en.wikipedia.org/wiki/Dimethyltryptamine" ??
 
Last edited by a moderator:
VeeEight said:
http://en.wikipedia.org/wiki/Dimethyltryptamine" ??

fun stuff!
 
Last edited by a moderator:
DMT said:
Ok, sorry! I just wanted to make sure they were correct before I turned it in so my instructor wouldn't take off points. I'll keep my posts to HW help from now on. Though, if one of the answers ended up being incorrect, the post would have turned into a homework help post right away ;)

Oh, that's ok. But there is no reason to post to HW help just to check answers to avoid point reductions. I think you should be genuinely confused before posting. Just my opinion.
 
You can use the online integrator provided by Wolfram to check your answers.

http://integrals.wolfram.com/index.jsp

Also, you could just differentiate your result and see if you recover the integrand.
 
vela said:
You can use the online integrator provided by Wolfram to check your answers.

http://integrals.wolfram.com/index.jsp

Also, you could just differentiate your result and see if you recover the integrand.

Wow! That is an amazing tool. Thanks for the link!
 

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