Question

Find an equation for the nth term of a geometric sequence where the second and fifth terms are -21 and 567, respectively.

Answer 1

you tried ?
you know the formula.
plug in alues

Answer 2

*values

Answer 3

2nd term = -21

n=2, a2 = -21

Answer 4

Oh I just noticed it is geometric

Answer 5

yep,
so formula is
\(\Large a_n = a_1 r^{n-1}\)

Answer 6

to find r do I just divide 567 by -21 ?

Answer 7

plug in those values

a2 = -21
n= 2

you will get one equation in a1 and r

Answer 8

then plug in
a5 = 567
n=5

you will get another equation in a1 and r

Answer 9

\[a _{n} = 6 * -27^{n-1}\]

Answer 10

\(-21= a_1 r\)
\(567 =a_1 r^4\)

Answer 11

divide those

Answer 12

you will get r^3

Answer 13

divide what