#2433 fails to integrate function

open
nobody
5
2012-12-04
2012-06-27
Anonymous
No

This seems to be a bug, though it can integrate it fine after simplification:

(%i1) i2 : (x^2-4)*asin(sqrt(16-4*x^2)*sqrt(4-x^2)/(2*x^2-8)) $
(%i2) i3 : 8 * integrate (i2, x, 0, 2);
expt: undefined: 0 to a negative exponent.

Discussion


  • Anonymous
    2012-06-27

    Also, that was reproduced in sage 5.0 and Maxima 5.27 + patches (from Git).

     
  • Aleksas
    Aleksas
    2012-06-27

    (%i1) i2 : (x^2-4)*asin(sqrt(16-4*x^2)*sqrt(4-x^2)/(2*x^2-8));
    (%o1) (x^2-4)*asin((sqrt(16-4*x^2)*sqrt(4-x^2))/(2*x^2-8))
    (%i2) i3:8*'integrate(i2,x,0,2);
    (%o2) 8*integrate((x^2-4)*asin((sqrt(16-4*x^2)*sqrt(4-x^2))/(2*x^2-8)),x,0,2)
    (%i3) radcan((sqrt(16-4*x^2)*sqrt(4-x^2))/(2*x^2-8));
    (%o3) -1
    (%i4) radcan(i3);
    (%o4) -4*integrate(%pi*x^2-4*%pi,x,0,2)
    (%i5) ev(%, nouns);
    (%o5) (64*%pi)/3

    not bug

    best
    Aleksas D