Question

Quick Question

Answer 1

\[a _{1}=3 , s _{3}=123/5 \]

Answer 2

find r

Answer 3

The answer is r= -6/5, r=1/5

Answer 4

How would I set up the question?

Answer 5

can you post the full question?

Answer 6

This is what the question says. In a geometric sequence: \[a _{1}=20, S _{3}=124/5\]

Answer 7

find r

Answer 8

s= summation

Answer 9

@agent0smith

Answer 10

Just use the formula for the sum of a geometric series.

S = a1 (1-r^n)/(1-r)

Plug in the a1 and the S, and n which is 3 and solve for r

Answer 11

You might have to do some factoring with the numerator,since it'll be a difference of two cubes and there's a formula for that

Answer 12

Alrighty I'll try it out

Answer 13

I ended up with 1 and 6/25 for my r..