1003085008

Level: 
Project ID: 
1003085008
Accepted: 
1
Clonable: 
0
Easy: 
1
A sequence \( \left( a_n \right)_{n=1}^{\infty} \) is defined by the recursive formula: \( a_1=1;\ a_{n+1}=-2a_n\text{, }n\in\mathbb{N} \). What is its third term?
\( 4 \)
\( 2 \)
\( -4 \)
\( \frac12 \)