1003107310

Level: 
Project ID: 
1003107310
Accepted: 
1
Clonable: 
0
Easy: 
0
We are given a sequence \( \left( a_n \right)^{\infty}_{n=1} \) defined recursively by: \( a_1=1,\ a_2=2\,;\ a_{n+2}=\frac12\left( a_{n+1}+a_n\right),\ n\in\mathbb{N} \). Find the sum of the first four terms of this sequence.
\( \frac{25}4 \)
\( \frac{63}8 \)
\( \frac{13}4 \)
\( \frac4{25} \)