- #1
Tsunoyukami
- 215
- 11
I'm having difficulty understanding this question - and if I am interpreting it correctly, how to go about doing so.
First, we will need the following theorem:
"Morera's Theorem If ##f## is a continuous function on a domain ##D## and if
$$\int_{\gamma} f(z) dz = 0$$
for every triangle ##\gamma## that lies, together with its interior, in ##D##, then ##f## is analytic on ##D##." (Complex Variables, 2nd. edition; Stephen D. Fisher, pg. 129)"24. Use Morera's Theorem and an interchange of the order of integration to show that each of the following functions is analytic on the indicated domain; find a power-series expansion for each function by using the known power series for the integrand and interchanging the summation and integration.
a) ##\int_{0}^{1} \frac{dt}{1 -tz}## on ##|z| < 1##" (Complex Variables, 2nd. edition; Stephen D. Fisher, pg. 134)I have not attempted this problem because I am unsure of what exactly it is asking me to do. Here is my interpretation:
1) Write the integral with respect to z (be sure to change the bounds of the integral as well) as opposed to z.
2) Apply Morera's Theorem to show that the function is analytic.
3) Use the "known power series for the integrand" to write out a power series...as in basically copy out the known power series?I'm just not really sure what to do or how to go about doing so. If my above interpretation is correct how do I complete the first step? Do I simply write:
##\int_{0}^{1} \frac{dt}{1 -tz}## on ##|z| < 1##
##\int_{0}^{2\pi} \frac{dz}{1-tz}## on ##0 \leq t \ leq 1##
I feel like that is almost blatantly incorrect...
Any guidance is very much appreciated - thanks!
First, we will need the following theorem:
"Morera's Theorem If ##f## is a continuous function on a domain ##D## and if
$$\int_{\gamma} f(z) dz = 0$$
for every triangle ##\gamma## that lies, together with its interior, in ##D##, then ##f## is analytic on ##D##." (Complex Variables, 2nd. edition; Stephen D. Fisher, pg. 129)"24. Use Morera's Theorem and an interchange of the order of integration to show that each of the following functions is analytic on the indicated domain; find a power-series expansion for each function by using the known power series for the integrand and interchanging the summation and integration.
a) ##\int_{0}^{1} \frac{dt}{1 -tz}## on ##|z| < 1##" (Complex Variables, 2nd. edition; Stephen D. Fisher, pg. 134)I have not attempted this problem because I am unsure of what exactly it is asking me to do. Here is my interpretation:
1) Write the integral with respect to z (be sure to change the bounds of the integral as well) as opposed to z.
2) Apply Morera's Theorem to show that the function is analytic.
3) Use the "known power series for the integrand" to write out a power series...as in basically copy out the known power series?I'm just not really sure what to do or how to go about doing so. If my above interpretation is correct how do I complete the first step? Do I simply write:
##\int_{0}^{1} \frac{dt}{1 -tz}## on ##|z| < 1##
##\int_{0}^{2\pi} \frac{dz}{1-tz}## on ##0 \leq t \ leq 1##
I feel like that is almost blatantly incorrect...
Any guidance is very much appreciated - thanks!