Example 8.23.  Evaluate  [Graphics:Images/IntegralsBranchPointsMod_gr_21.gif],  where  [Graphics:Images/IntegralsBranchPointsMod_gr_22.gif].  

[Graphics:Images/IntegralsBranchPointsMod_gr_23.gif]

Explore Solution 8.23.

Enter the function and  [Graphics:../Images/IntegralsBranchPointsMod_gr_28.gif]  and locate the isolated singularities.

[Graphics:../Images/IntegralsBranchPointsMod_gr_29.gif]




[Graphics:../Images/IntegralsBranchPointsMod_gr_30.gif]

 

 

 

Which pole(s) are non-zero ?

[Graphics:../Images/IntegralsBranchPointsMod_gr_31.gif]





[Graphics:../Images/IntegralsBranchPointsMod_gr_32.gif]

[Graphics:../Images/IntegralsBranchPointsMod_gr_33.gif]

 

 

 

Compute the residues at  [Graphics:../Images/IntegralsBranchPointsMod_gr_34.gif],  and use the residue calculus to compute the value of the integral.

[Graphics:../Images/IntegralsBranchPointsMod_gr_35.gif]

[Graphics:../Images/IntegralsBranchPointsMod_gr_36.gif]

[Graphics:../Images/IntegralsBranchPointsMod_gr_37.gif]

 

 

 

 

 

[Graphics:../Images/IntegralsBranchPointsMod_gr_38.gif]

[Graphics:../Images/IntegralsBranchPointsMod_gr_39.gif]

[Graphics:../Images/IntegralsBranchPointsMod_gr_40.gif]

 

 

 

Aside. We can use Mathematica's built in "PrincipalValue" option to evaluate this definite integral .

[Graphics:../Images/IntegralsBranchPointsMod_gr_41.gif]




[Graphics:../Images/IntegralsBranchPointsMod_gr_42.gif]

Which is also the correct answer.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

(c) 2006 John H. Mathews, Russell W. Howell