Give an explective rule for the following geometric sequence:

A4=-192
A9=-196608

Attempt at Solution:

-192=A1(R)^3
-196608=A1(R)^8
-196416=A1(R)^8 + A1(R)^3
???

Any help greatly appreciated!! Math exam tomorrow.

Question

Give an explective rule for the following geometric sequence:

A4=-192
A9=-196608

Attempt at Solution:

-192=A1(R)^3
-196608=A1(R)^8
-196416=A1(R)^8 + A1(R)^3
???

Any help greatly appreciated!! Math exam tomorrow.

asnaseer · Answer

instead of adding, it would be better to divide A9 by A4 because then A1 cancels out.

anonymous · Answer

Ah so 
1024=(r)^8/(r)^5)
Now what?

asnaseer · Answer

now simplify the right-hand-side

anonymous · Answer

1024=r^3
r=10.079
The real ratio is 4, I dont think I divided the variables with exponents right.

asnaseer · Answer

no, it should be:$$\frac{r^8}{r^3}=r^5=1024$$

anonymous · Answer

Oh i see I mistyped when I divided. Thank you so much, I think ive got the hang of this now.

asnaseer · Answer

great! I'm glad I was able to help :)