For the recurrence $a_n = 1.8a_{n-1} + 0.4a_{n-2}$ with characteristic roots $r_1 = 2$ and $r_2 = -0.2$, the general solution is $a_n = c_1 \cdot 2^n + c_2 \cdot (-0.2)^n$. For large $n$, which term dominates the behavior?