Question

Find the general term a[n] for the geometric sequence.
a[1]=-5 and a[2]=15

a[n] =

Answer 1

the general n term formula for geometric sequence is
\(a[n] = a[1] r^{n-1} \)
where r= common ratio = next term / current term
here r= 15/ (-5) = .... ?

Answer 2

-3

Answer 3

yes, so just plug in values of r and a[1] in that formula !

Answer 4

so then would the correct response be
a[n] = -5(-3)^n-1....?

Answer 5

yes, that would be correct, just don't miss on brackets
a[n] = -5(-3)^{n-1}

Answer 6

\(a[n] = -5(-3)^{n-1}\)

Answer 7

Thank you very much

Answer 8

welcome ^_^