Brilliant

Excel in math and science.

Log in with Facebook Log in with Google Log in with email

Join using Facebook Join using Google Join using email

Forgot password? New user? Sign up

Existing user? Log in

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 $a+b+c$ .

View solutions

Your answer seems reasonable. Find out if you're right!

Sign up to access problem solutions.

That seems reasonable. Find out if you're right!

Sign up to save your progress!

Log in with Facebook Log in with Google Log in with email

Join using Facebook Join using Google Join using email

Forgot password? New user? Sign up

Existing user? Log in

by Jake Lai

×

Problem Loading...

Note Loading...

Set Loading...