[tex]a_n=4(a_{n-1})[/tex]
means the nth term is 4 times the previous term
first term is 0.5
means the next one is 0.5 times 4 or 2
hum, geometric sequence
we can write it as
[tex]a_n=a_1(r)^{n-1}[/tex]
where
[tex]a_n[/tex] is the nth term
[tex]a_1[/tex] is the first term
[tex]r[/tex] is the common ratio (what you multiply each term by to get the next term)
[tex]n[/tex] is which term
so first term is 0.5
common ratio is 4
so therfor
[tex]a_n=0.5(4)^{n-1}[/tex]
answer is E
