Opened 3 years ago

Closed 2 years ago

#22672 closed defect (wontfix)

Definite integral of (1-x)^(1/5)/sqrt(x) crashes with both GSL and Maxima

Reported by: rws Owned by:
Priority: major Milestone: sage-duplicate/invalid/wontfix
Component: calculus Keywords:
Cc: Merged in:
Authors: Reviewers:
Report Upstream: N/A Work issues:
Branch: Commit:
Dependencies: Stopgaps:

Description 

sage: ((1-x)^(1/5)/sqrt(x)).nintegral(x,2,3)
...
TypeError: ECL says: Error executing code in Maxima: 

sage: ((1-x)^(1/5)/sqrt(x)).integrate(x,2,3,hold=True)
integrate((-x + 1)^(1/5)/sqrt(x), x, 2, 3)
sage: _.n()
...
Exception ValueError: ValueError('negative number to a fractional power not real',) in 'sage.calculus.integration.c_ff' ignored

Change History (5)

comment:1 Changed 3 years ago by rws

The correct value would be 0.554731721677539 + 0.403036187432365*I.

comment:2 Changed 2 years ago by zimmerma

I'm not sure, but I believe numerical integration only works for real functions: 

sage: numerical_integral(I,0,1)
...
TypeError: unable to simplify to float approximation

Here, the function is complex in [2,3]: 

sage: n((1-2)^(1/5))
0.809016994374947 + 0.587785252292473*I

comment:3 Changed 2 years ago by rws

  • Milestone changed from sage-8.0 to sage-duplicate/invalid/wontfix
  • Status changed from new to needs_review

Yes right.

comment:4 Changed 2 years ago by rws

  • Status changed from needs_review to positive_review

comment:5 Changed 2 years ago by embray

  • Resolution set to wontfix
  • Status changed from positive_review to closed

Closing tickets in the sage-duplicate/invalid/wontfix module with positive_review (i.e. someone has confirmed they should be closed).

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