Example
8.15. Evaluate
.
![[Graphics:Images/IntegralsRationalMod_gr_62.gif]](../Images/IntegralsRationalMod_gr_62.gif)
Explore Solution 8.15.
Enter the function
and
locate the singularities.
![[Graphics:../Images/IntegralsRationalMod_gr_73.gif]](../Images/IntegralsRationalMod_gr_73.gif)
Determine which poles lie in the upper half plane ?
![[Graphics:../Images/IntegralsRationalMod_gr_75.gif]](../Images/IntegralsRationalMod_gr_75.gif)
![[Graphics:../Images/IntegralsRationalMod_gr_76.gif]](../Images/IntegralsRationalMod_gr_76.gif)
Compute the residues at
,
and use the residue calculus to compute the value of the
integral.
![[Graphics:../Images/IntegralsRationalMod_gr_79.gif]](../Images/IntegralsRationalMod_gr_79.gif)
![[Graphics:../Images/IntegralsRationalMod_gr_80.gif]](../Images/IntegralsRationalMod_gr_80.gif)
![[Graphics:../Images/IntegralsRationalMod_gr_81.gif]](../Images/IntegralsRationalMod_gr_81.gif)
Or, we can use Mathematica's integral table and evaluate the integral.
![]()
However, for this simple integral Mathematica's can find the correct answer without resorting to the PrincipalValue option.
![[Graphics:../Images/IntegralsRationalMod_gr_85.gif]](../Images/IntegralsRationalMod_gr_85.gif)
The above answer is correct too.