Question

Write an explicit formula for the geometric sequence below and use it to find the 9th term. 256, 64, 16, 4, . . .

Answer 1

im doing this problem right now---

ok so a1=256 a2=64 a3=15 a4=4... find a9

the sequence divides by 1/4 every term

an=a1*r^n-1

an=(256)*(1/4)^n-1

replace n with 9

A9=(256)*(1/4)^9-1

A9=(256)*(1/4)^8

=(256)*(1/4)

A9=64^8

1/256 or a9= 0.00390625