If the recursive formula is:
a(n)=4*a(n-1)
And a1=1/2
This is a geometric sequence because each term is a constant multiple of the previous term, this constant multiple is called the common ratio. Any geometric sequence can be expressed as:
a(n)=ar^(n-1), a(n)=nth term, a=initial term, r=common ratio, n=term number
In this case, a=1/2 and r=4 so
a(n)=(1/2)(4^(n-1)), so the first four terms are:
4^0/2, 4^1/2, 4^2/2, 4^3/2
1/2, 4/2, 16/2 64/2
1/2, 2, 8, 32
