Identify the non-homogeneous part f(n)f(n)f(n) in the recurrence an=2an−1+4n−1a_n = 2a_{n-1} + 4n - 1an=2an−1+4n−1.
2an−12a_{n-1}2an−1
4n−14n - 14n−1
222
an−2an−1a_n - 2a_{n-1}an−2an−1