9000063803

Level: 
Project ID: 
9000063803
Accepted: 
1
Clonable: 
0
Easy: 
1
We are given the sequence \(\left (\cos n \frac{\pi }{4}\right )_{n=1}^{\infty }\). Find the sum of the first six terms of this sequence.
\(-\frac{2+\sqrt{2}} {2} \)
\(-\frac{\sqrt{2}} {2} \)
\(- 1\)
\(0\)