how do i find r in a geometric sequence?

1,1/3,1/9,1/27

Question

how do i find r in a geometric sequence?

1,1/3,1/9,1/27

anonymous · Answer

Divide 
2nd term / 1st term

Divide again to verify
3rd term / 2nd term

anonymous · Answer

ok well, first off, this isnt a geometric sequence right?

anonymous · Answer

since its not a common ratio

anonymous · Answer

3rd/2nd=2nd/1st=r
so to know it is geometric we must to devide 
for arithmetic we have to minus
2nd terms -1st terms=n

anonymous · Answer

It is a GM
There is a common ratio

anonymous · Answer

well i know that the 2nd term that when multiplied by 3 gives me the 3rd and when done once more gives me the third term, is that enough to say its a geometric sequence, its clear i dont know how to to do 1/3-1

anonymous · Answer

so its 3?

anonymous · Answer

$$\frac{ 1 }{ 3 }\div1 = \frac{ 1 }{ 3}$$

anonymous · Answer

no its 1/3 

2nd and 3rd terms

1/9*3/1=1/3

anonymous · Answer

$$\frac{ 1 }{9 }\div \frac{ 1 }{ 3}=\frac{ 1 }{3 }$$

anonymous · Answer

-_-im dumb, thnx :)