The integration operator ranges from:
exact [trivial], excellent, convenient, pure scrap
... or fails. The cause of failure is exposed here.
Grand Doctors: please have a look and solution next SS.
Cheers ... Jean

Bug Integration.sm (21,69 KiB) scaricato 1416 volta(e).

... more than puzzling:
1. int(,,,,) not defined
2. result above max allowed
3. 'x' not defined
What's next ? => bed time