Cos I can
Calculus
Level
4
If
\[\sum_{n=1}^{\infty} \frac{\cos n}{n}\]
can be expressed in the form \(-\frac 12 \ln(a-b\cos c)\), where \(a,b,\) and \(c\) are positive integers, find \(a+b+c\).
by
Jake Lai