作者t0444564 (艾利歐)
看板NTU-Exam
標題[試題] 109上 蔡宜洵 複分析導論 期中考
時間Tue Nov 17 14:30:53 2020
課程名稱︰複分析導論
課程性質︰數學系大三必修
課程教師︰蔡宜洵
開課學院:理學院
開課系所︰數學系
考試日期︰2020年11月12日(四)
考試時限:13:20-15:10,共計110分鐘,最後加五分鐘。
試題 :
Complex Analysis
November 12, 2020
Total points: 105
Note. 1) Your arguments and calculation details must be clear and complete;
the auxiliary theorems needed for any claim of your results must be
explicitly indicated. Failing to do so may result in loss of partial or
full points.
1. Let D be the open disk, centered at 0, of radius r.
r
z 2020 n
i) (15 points) Use Rocuhe theorem to show that the equation e - e z = 0
has exactly n roots (counted with multiplicity) in D .
1
ii)(10 points) Replace D by D and ask for D which encloses all the above
1 r r
n roots. Find the smallest r that can be obtained by your method in i).
+∞ e^(ax)
2. (20 points) Compute ∫ -------- dx, 0 < a < 1.
-∞ 1+2e^x
3. (20 points) Let f(z)∈Hol(C). Suppose that there exist R > 0, C > 0 and a
positive integer N such that |f(z)|≦C|z|^N for all |z| > R. Show that f(z)
is a polynomial of degree at most N. (hint: Cauchy's integral formula)
dz
4. (20 points) Compute the integeral ∫ --------, where C is the curve with
C z^4 -1
z(θ) = 2cos(2θ)e^(iθ), θ from 0 to 2π.
5. (20 points) Let f(z)∈Hol(C). Assume that f(z) is not a polynomial, Show
that given any R > 0, there exists z_1 with |z_1| > R and z_2 with |z_2| < 1
such that f(z_1) = f(z_2). (hint: open mapping theorem...etc.)
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