How do you evaluate dxx22x+2 from [0,2]?

1 Answer
Feb 4, 2017

π2

Explanation:

The denominator cannot be factored, so complete the square and see what you can do in the way of u-substitution.

2011(x22x+11)+2dx

2011(x22x+1)1+2dx

201(x1)2+1dx

Now let u=x1. Then du=dx. We also adjust our bounds of integration accordingly.

111u2+1du

This is a standard integral.

11arctan(u)

20arctan(x1)

Evaluate using the 2nd fundamental theorem of calculus.

arctan(21)arctan(01)=arctan(1)arctan(1)=π4(π4)=π2

Hopefully this helps!