1549312215-Complex_Analysis_for_Mathematics_and_Engineering_5th_edition__Mathews

218 CHAPTER. 6 • COMPLEX INTEGRATION

y

d

c

Figure 6. 19 Integration over a standard region, where C = Ca + C4.

We give two proofs. The first, by Augustin Cauchy, is more intuitive but

requires the additional hypothesis that f' is continuous.

In 1883, Edward Goursat (1858-1936) produced a proof that does not require

the continuity of f '·