Question

write the explicit formula for the geometric sequence.0.5, -0.1, 0.02, -0.004

Answer 1

is it:
an= 0.5*(-0.2)^(n-1)

Answer 2

\[.5*\sum_{i=0}^{3}(-1/5)^i\]

Answer 3

sequence, not series, so summation is not used

Answer 4

you're right, .5*(-1/5)^n, for n=0,1,2,3

Answer 5

ok but I can leave it a decimal right?

Answer 6

unless , they ask for in fraction , you can

Answer 7

so you almost had it @music101. Usually in math you don't convert to decimal unless necessary, leave as fraction

Answer 8

ok & also isn't it ...(-1/5) to the n-1?

Answer 9

if you start with 1, that's ok, just state your starting and ending indices

Answer 10

also, I already submitted the answer and all the answer options were in decimal so I think im good?

Answer 11

I wouldn't worry about it

Answer 12

ok so it is (-1/5)^n-1 right? or no? because it starts @ i=1

Answer 13

right, starts with 1 ends with 4, in the form you have it

Answer 14

ok thnks

Answer 15

np