the sum of the term in a geometric sequence
Sn=[tex] \frac{a1(1-r^n)}{1-r} [/tex]
where
there are n terms
r is common ratio
a1 is first term
Sn=[tex] \frac{20(1-(1/4)^5)}{1-(1/4)} [/tex]
Sn=[tex] \frac{20(1-(1/1024))}{3/4} [/tex]
Sn=[tex] \frac{20(1023/1024)}{3/4} [/tex]
Sn=[tex] \frac{1705}{64} [/tex]
