= Solution
One standard form of the <Cauchy integral formula> is this: if $f$ is <holomorphic> on an <open set> containing a <contour> that is a <simple closed curve> $\Gamma$ and its interior, and $\Gamma$ has <positive orientation of a contour>, then for every point $w$ inside it,
$$
\boxed{f(w)=\frac1{2\pi i}\int_\Gamma\frac{f(z)}{z-w}\,dz.}
$$
The hypothesis includes the contour itself; <singularities> on the contour are excluded. In particular, the formula applies on a <circle> whose closed <disk> is contained in the domain of <holomorphy>.
Back to article page
