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5 votes
Find an equation for the nth term of the sequence.
-2, -8, -32, -128, ...

User Gnodab
by
5.9k points

1 Answer

4 votes
k, so we see it is not increasing by same value, so it isn't arithmetic sequence
geometric, times 4 each time

f(n)=a1(r)^(n-1)
r=common ratio
a1=first term

so
first term is -2 and common ratio is 4

f(n)=-2(4)^(n-1)
or simply

f(n)= ((-1)/(2) )(4^n)
User Violeta
by
7.0k points
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