Results 1 to 3 of 3

Math Help - Anyone want to check this solution on WolframAlpha

  1. #1
    Member
    Joined
    May 2009
    Posts
    211

    Anyone want to check this solution on WolframAlpha

    Well this is part of a larger problem I'm doing. The thing is that I'm checking my answer on WolframAlpha gives me a different solution. I've gone over the integral several times, but I'm unable to find my error (If there's any).

    Here's the link:

    integral [pi*[(2-sinx)^2 - (2-cosx)^2]] from 0 to pi/4 - Wolfram|Alpha

    Thanks. (bow)
    Follow Math Help Forum on Facebook and Google+

  2. #2
    Junior Member
    Joined
    Apr 2009
    Posts
    73
    Quote Originally Posted by Arturo_026 View Post
    Well this is part of a larger problem I'm doing. The thing is that I'm checking my answer on WolframAlpha gives me a different solution. I've gone over the integral several times, but I'm unable to find my error (If there's any).

    Here's the link:

    integral [pi*[(2-sinx)^2 - (2-cosx)^2]] from 0 to pi/4 - Wolfram|Alpha

    Thanks. (bow)
    Well, I stuck in 45 instead of pi/4 (to compute it in degrees, and wolfram alpha gave me the correct answer, which is indeed  \frac{1}{2}(-9+8\sqrt{2}) \pi
    To get this you expand the integral out:
    \pi \int{(4-4sinx+sin^2x)-(4-4cosx+cos^2(x)}= \int{4-4-4sinx+4cosx +sin^2x -cos^x} =\int{4(cosx-sinx)-cos(2x)}
    having left out the dxs and the bounds. Integrate, stick in your boundaries and you should get the same as wolfram alpha.
    Note:This is also the same as 4.5+\frac{8}{\sqrt{2}}
    Follow Math Help Forum on Facebook and Google+

  3. #3
    Member
    Joined
    May 2009
    Posts
    211
    I finally caught my mistake. I forgot to calculate for sin(0) and cos(0) because I got used to neglecting those when solving polynomials since almost always they give you zero.

    Thanks.
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. Integration...Please check my solution
    Posted in the Calculus Forum
    Replies: 1
    Last Post: May 14th 2010, 10:27 AM
  2. could some check solution please
    Posted in the Pre-Calculus Forum
    Replies: 2
    Last Post: February 17th 2010, 10:46 PM
  3. Check my limits Solution
    Posted in the Pre-Calculus Forum
    Replies: 4
    Last Post: October 7th 2009, 07:58 AM
  4. galois -check solution
    Posted in the Advanced Algebra Forum
    Replies: 5
    Last Post: March 24th 2009, 07:34 PM
  5. Can you check my solution? (limits)
    Posted in the Pre-Calculus Forum
    Replies: 1
    Last Post: February 11th 2008, 07:50 PM

Search Tags


/mathhelpforum @mathhelpforum