*Due Friday October 10*

1. Evaluate the
integral _{}, *a* real, by
closing the contour with a large semicircle at infinity—and prove that the
semicircle gives a zero contribution.

2. Evaluate the integral _{} by closing with a
large semicircle at infinity (upper half plane or lower half plane?). Here *ε*
is a very small real quantity, as usual. Does the value of the integral depend on the *sign* of *ε*? What about the sign
of *k*? (*k*
is real.) Explain.

**Shankar 5.4.2, 5.4.3.**