Aha. $1$.

1 files changed, 1 insertions, 1 deletions

diff --git a/Problem Set 3.page b/Problem Set 3.page
index daae048..b1011b9 100644
--- a/Problem Set 3.page
+++ b/Problem Set 3.page
@@ -32,7 +32,7 @@ Use Fourier series to solve the wave equation in the case of a vibrating ring.
 $$ f(r,\theta) = \sum_n a_n(r)e^{in\theta} $$
 as a Fourier series whose coefficients depend on $r$.  Use the Cauchy-Riemann equations in polar coordinates to derive the Laurent series expansion of $f$ without using the map $z \mapsto e^{iz}$. 
 
-9. Let $f(z)$ be a holomorphic function defined on a region that contains the disk of radius $1$.  Derive the following variant of the Cauchy integral formula:
+9. Let $f(z)$ be a holomorphic function defined on a region that contains the disk of radius 1.  Derive the following variant of the Cauchy integral formula:
 $$ f(z) = \frac{1}{2\pi} \int_0^{2\pi} \frac{f(e^{i\theta})}{1 - e^{-i\theta}z} d\theta $$
 Hint: Expand the right hand side using the formula for a geometric series:
 $$ \frac{1}{1-x} = \sum_{n=0}^{\infty} x^n $$