Complex Analysis: Theory and Applications · Problem 5.2.12

Elementary Functions — Howell & Matthews

Mathematics — Complex Analysis · complex-logarithm-mapping

Problem

Show that the mapping w=Log(z)w = \mathrm{Log}(z) maps ((a)) the ray {z=reiθ:r>0, θ=π3}\{z = re^{i\theta} : r > 0,\ \theta = \frac{\pi}{3}\} one-to-one and onto the horizontal line {(u,v):v=π3}\{(u,v) : v = \frac{\pi}{3}\}. ((b)) the semicircle {z=2eiθ:−π2≤θ≤π2}\{z = 2e^{i\theta} : -\frac{\pi}{2} \leq \theta \leq \frac{\pi}{2}\} one-to-one and onto the vertical line segment {(ln⁡2,v):−π2≤v≤π2}\{(\ln 2, v) : -\frac{\pi}{2} \leq v \leq \frac{\pi}{2}\}.

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