A First Course in Complex Analysis · Problem 8

Consequences of Cauchy's Theorem — Beck, Marchesi, Pixton & Sabalka

Mathematics — Complex Analysis · complex-integration

Problem

Compute ∫γf\int_{\gamma} f for the following functions ff and paths γ\gamma: (a) f(z)=z2f(z) = z^2 and γ(t)=t+it2\gamma(t) = t + it^2, 0≤t≤10 \leq t \leq 1. (b) f(z)=zf(z) = z and γ\gamma is the semicircle from 11 through ii to −1-1. (c) f(z)=exp⁡(z)f(z) = \exp(z) and γ\gamma is the line segment from 00 to a point z0z_0. (d) f(z)=∣z∣2f(z) = |z|^2 and γ\gamma is the line segment from 22 to 3+i3 + i. (e) f(z)=z+1zf(z) = z + \frac{1}{z} and γ\gamma is parametrized by γ(t)\gamma(t), 0≤t≤10 \leq t \leq 1, and satisfies Im⁡γ(t)>0\operatorname{Im}\gamma(t) > 0, γ(0)=−4+i\gamma(0) = -4 + i, and γ(1)=6+2i\gamma(1) = 6 + 2i. (f) f(z)=sin⁡(z)f(z) = \sin(z) and γ\gamma is some piecewise smooth path from ii to π\pi.

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