#596 wrong results for integrate(sqrt(cos(x)+1));

closed
nobody
None
5
2006-02-23
2004-09-19
Anonymous
No

integrate(sqrt(cos(x)+1),x);
==>
2 SQRT(2) SIN(x)
------------------------------------
2
SIN (x)
(COS(x) + 1) SQRT(------------- + 1)
2
(COS(x) + 1)
This is wrong!

Discussion

  • Raymond Toy

    Raymond Toy - 2004-11-01

    Logged In: YES
    user_id=28849

    Why is this wrong? If I differentiate the result, I get:

    trigsimp(diff(%,x));
    (%o35) -(sqrt(2)*sin(x)^2-2*sqrt(2)*cos(x)-2*sqrt(2))
    /((cos(x)+1)*sqrt(2*cos(x)+2))
    (%i36) factor(%);

    (%o36) -(sin(x)^2-2*cos(x)-2)/(cos(x)+1)^(3/2)

    (%i37) ev(%,sin(x)^2=1-cos(x)^2);

    (%o37) -(-cos(x)^2-2*cos(x)-1)/(cos(x)+1)^(3/2)
    (%i38) factor(%);

    (%o38) sqrt(cos(x)+1)

     
  • Raymond Toy

    Raymond Toy - 2006-02-23

    Logged In: YES
    user_id=28849

    Closing this report. The derivative matches the integrand,
    after some manipulations.

     
  • Raymond Toy

    Raymond Toy - 2006-02-23
    • status: open --> closed
     

Get latest updates about Open Source Projects, Conferences and News.

Sign up for the SourceForge newsletter:





No, thanks