Which geometric series represents 0. as a fraction?
a. 1/4+1/40+1/400+1/4000
b. 1/40+1/400+1/4000+1/4
c. 4/10+4/100+4/1000+4/1
d. 1/10+1/100+1/1000+1/1

If you look at each decimal place it is in decreasing powers of 10, ie...

after the decimal point in our number system you have columns with coefficient values of 10^-1, 10^-2, 10^-3, etc

1/10, 1/100, 1/1000 etc and in this case we have

4/10, 4/100, 4/1000, etc

So it would be C.

Technically the sequence is:

a(n)=(4/10)(1/10)^(n-1)  if we are going to be talking about geometric sequences...

Do you need with the x value for the minimum? its always between the two intercepts for a parabola