If an=2an−1a_n = 2a_{n-1}an=2an−1, what is the relation between a10a_{10}a10 and a9a_9a9?
a10=2a9a_{10} = 2a_9a10=2a9
a10=a9a_{10} = a_9a10=a9
a10=10a9a_{10} = 10a_9a10=10a9
a10=2+a9a_{10} = 2+a_9a10=2+a9