Problem
ALG-B1-M12-P014 Variant 4, Problem 2
#14
★★★☆☆ Level 3 of 5
\(u_0=3\), \(u_1=7\), \(u_{n+2}=2u_{n+1}-u_n\). Find \(u_n\).
The difference is constant.
\(u_{n+1}-u_n=4\), hence \(u_n=4n+3\).
Mock olympiad problem. Tags: recurrence.