#2588 Maxima ignores input to asksign

None
open
nobody
5
2014-07-22
2013-06-05
Barton Willis
No

OK:

(%i1) integrate(x^mu * atan(x),x);
"Is  "mu+1"  zero or nonzero?"zero;

(%o1) -(%pi*log(x^2+1)+2*%i*li[2](%i*x+1)-2*%i*li[2](1-%i*x)-4*atan(x)*log(x))/4

Not OK--the antiderivative isn't valid when mu + 1 = 0

(%i2) integrate(x^mu * acos(x),x);
"Is  "mu+1"  zero or nonzero?"zero;
(%o2) -((mu+1)*integrate((sqrt(1-x)*x*sqrt(x+1)*%e^(mu*log(x)))/((mu+1)*x^2-mu-1),x)-x*%e^(mu*log(x))*atan2(sqrt(1-x)*sqrt(x+1),x))/(mu+1)

Discussion

  • Robert Dodier
    Robert Dodier
    2013-07-22

    • labels: --> Lisp Core - Integration, Lisp Core - Assume
    • Description has changed:

    Diff:

    --- old
    +++ new
    @@ -1,14 +1,17 @@
     OK:
    
    +~~~~
     (%i1) integrate(x^mu * atan(x),x);
     "Is  "mu+1"  zero or nonzero?"zero;
    
     (%o1) -(%pi*log(x^2+1)+2*%i*li[2](%i*x+1)-2*%i*li[2](1-%i*x)-4*atan(x)*log(x))/4
    +~~~~
    
     Not OK--the antiderivative isn't valid when mu + 1 = 0
    
    +~~~~
     (%i2) integrate(x^mu * acos(x),x);
     "Is  "mu+1"  zero or nonzero?"zero;
     (%o2) -((mu+1)*integrate((sqrt(1-x)*x*sqrt(x+1)*%e^(mu*log(x)))/((mu+1)*x^2-mu-1),x)-x*%e^(mu*log(x))*atan2(sqrt(1-x)*sqrt(x+1),x))/(mu+1)
    +~~~~
    
    -
    
     
  • Robert Dodier
    Robert Dodier
    2013-07-22

    I put leading and trailing tildes (~~~~) around Maxima i/o, and assigned labels.