NIntegrate(cos(x), {x, 0, pi}) should return 0,but return 1.3465790982269965E-16

[zhoukang]

maybe we can check the integrate first ,if has F(x),just subtract F(a)-F(b) and return?

[Axel Kramer]

We can try to define an epsilon value in NIntegrate for which the output will be 0? See: http://stackoverflow.com/q/3728246/3805428

[zhoukang]

yes，that's good!even we can implement an interface which can send an epsilon by user

[Axel Kramer]

I implemented this commit: 3cbcffb

You can now set a PrecisionGoal like this:

NIntegrate(1/Sin(Sqrt(x)), {x, 0, 1}, PrecisionGoal->10)

The default PrecisionGoal is set to 16