<html><head><meta name="color-scheme" content="light dark"></head><body><pre style="word-wrap: break-word; white-space: pre-wrap;">Je-li $f$ sudá spojitá funkce a
$\varphi (t) =  \cos (t) + i \sin (t)  $ pro
$t \in [0,2 \pi]$, pak
$$
\int _{\varphi } f(z) dz = 0 \quad.
$$
</pre></body></html>