complex-analysis/ForStudents/листки Забродина/listok12.tex

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\documentclass[11pt,a4paper]{article}
\usepackage[cp1251]{inputenc}
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\usepackage{amssymb,amsfonts,amsmath}
\usepackage{xspace}
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\newcounter{zadacha}
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\newcommand*{\nz}{%
\par\medskip\refstepcounter{zadacha}
\textbf{\thezadacha.} }
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\newcommand*{\C}{\ensuremath{\mathbb C}\xspace}
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\begin{document}
\begin{center}\large\sc
Òåîðèÿ ôóíêöèé êîìïëåêñíîãî ïåðåìåííîãî -- 2025\\ Ëèñòîê 12
\end{center}
\nz
Ïóñòü ðåãóëÿðíàÿ âåòâü $g(z)$ ôóíêöèè $\sqrt{z^2-4}$ îïðåäåëåíà â îáëàñòè $D$,
ïðåäñòàâëÿþùåé ñîáîé êîìïëåêñíóþ ïëîñêîñòü ñ ðàçðåçîì ïî ïîëóîêðóæíîñòè
$|z|=2$, ${\rm Im} z\geq 0$, ïðè÷åì ãëàâíàÿ ÷àñòü ðÿäà Ëîðàíà ôóíêöèè $g(z)$
â îêðåñòíîñòè $\infty$ ðàâíà $z$. Âû÷èñëèòå èíòåãðàë
$$
I=\oint _{|z|=1}\frac{dz}{g(z)-3z}.
$$
\nz
Âû÷èñëèòå èíòåãðàë
$$
\oint_{|z|=\frac{1}{2}}\frac{dz}{(2+g(z))\sin z},
$$
ãäå $g(z)$ -- îäíîçíà÷íàÿ âåòâü ôóíêöèè $\sqrt{z-1}$ â êðóãå
$|z|<\frac{1}{2}$, òàêàÿ, ÷òî $g(0)=i$.
\nz
Ïóñòü $f(z)$ -- ðåãóëÿðíàÿ âåòâü ôóíêöèè $\sqrt[3]{2z-8}$ â êîìïëåêñíîé ïëîñêîñòè
ñ ðàçðåçîì ïî ëó÷ó $[4, 4-i\infty ]$ òàêàÿ, ÷òî $f(8)=-1-i\sqrt{3}$. Âû÷èñëèòå èíòåãðàë
$$
I=\oint _{|z-2|=3/2}\frac{dz}{f(z)-z+2}.
$$
\nz
Âû÷èñëèòå èíòåãðàëû ñ ïîìîùüþ âû÷åòîâ:
à) $\displaystyle{\int\limits_{-1}^{1}
\frac{dx}{\sqrt{1-x^2}}}\,\,$;
á) $\displaystyle{\int\limits_{0}^{1}
\sqrt{\frac{1-x}{x}}\, dx} \,\,$.
\nz
Âû÷èñëèòå èíòåãðàë ñ ïîìîùüþ âû÷åòîâ:
$\displaystyle{\int\limits_{0}^{\infty}
\frac{x^{\alpha -1}}{x+1}\,dx} \,\,$ ($0<\alpha <1$).
\nz
Âû÷èñëèòå èíòåãðàëû ñ ïîìîùüþ âû÷åòîâ:
à) $\displaystyle{\int\limits_{0}^{1}\left (\frac{x}{1-x}\right )^{\alpha}
\frac{dx}{x+1}\,\,}$ ($-1<\alpha <1$);
á) $\displaystyle{\int\limits_{1}^{2}\sqrt[5]{\frac{(2-x)^3}{(x-1)^3}}\, dx}$;\\
â) $\displaystyle{\int\limits_{-2}^{2}\frac{dx}{\sqrt[4]{(2+x)^2 (4-x^2)}}}\,$.
\nz
Âû÷èñëèòå èíòåãðàëû ñ ïîìîùüþ âû÷åòîâ:
à) $\displaystyle{\int\limits_{0}^{\infty}\frac{dx}{x^3+1}}\,$;
á) $\displaystyle{\int\limits_{0}^{\infty}\frac{\log x \, dx}{x^2+a^2} \,\,\, (a>0)}$;
â) $\displaystyle{\int\limits_{0}^{\infty}\frac{\log x \, dx}{(x+1)(x+2)^2}\,}$;\\
ã) $\displaystyle{\int\limits_{0}^{\infty}\frac{\log x \, dx}{x^2-1}}\,$.
\nz
Âû÷èñëèòå èíòåãðàëû ñ ïîìîùüþ âû÷åòîâ:
à) $\displaystyle{\int\limits_{0}^{\infty}\left (\frac{\log x}{x-1}\right )^2 dx}$;
á) $\displaystyle{\int\limits_{0}^{\infty}\frac{\sqrt{x}\, \log x dx}{x^2+1}}$;
â) $\displaystyle{\int\limits_{-\infty}^{\infty}\frac{\log |x^2-1|}{x^2+1}\, dx}$;\\
ã) $\displaystyle{\int\limits_{0}^{\infty}
\frac{\log (1+x^2)}{x^2}\, \frac{dx}{1+x^2}}$.
\end{document}