Author Topic: Q4 TUT 5301  (Read 446 times)

Victor Ivrii

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Q4 TUT 5301
« on: October 26, 2018, 05:57:09 PM »
$\renewcommand{\Re}{\operatorname{Re}}$
$\renewcommand{\Im}{\operatorname{Im}}$
Evaluate the given integral using the technique of Example 10 of Section 2.3 of the Textbook;
indicate which theorem or result you used to obtain your answer.
$$
\int_\gamma \frac{dz}{z^2},
$$
where $\gamma$ is any curve in $\{z\colon \Re z>0\}$ joining $(1-i)$ to $(1+i)$.

Jeffery Mcbride

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Re: Q4 TUT 5301
« Reply #1 on: October 26, 2018, 06:05:27 PM »

\begin{equation*}
F( z) \ =\ \frac{-1}{z}\\
\\
The\ function\ is\ analytic\ in\ all\ of\ Re\ z\  >\ 0\\
\\
So\ we\ just\ want\ F( end\ point) \ -\ F( first\ point)\\
\\
F( 1-i) \ -\ F( 1\ +\ i)\\
\\
=\ \frac{-1}{1-i} \ +\ \frac{1}{1+i}\\
\\
=\ \frac{-1\ -\ i\ +\ 1\ -\ i\ }{( 1-i)( 1+i)} \ \\
\\
=\ \frac{-2i}{-2}\\
\\
=\ i
\end{equation*}