Which recurrence relation has the characteristic equation r2−4=0r^2 - 4 = 0r2−4=0?
an=4an−1a_n = 4a_{n-1}an=4an−1
an=4an−2a_n = 4a_{n-2}an=4an−2
an=4an−1+4an−2a_n = 4a_{n-1} + 4a_{n-2}an=4an−1+4an−2
an=4an−1−4an−2a_n = 4a_{n-1} - 4a_{n-2}an=4an−1−4an−2