find the sum of the first 10 terms of geometric series with a[2]=(1)/(2) and r=2

2 answers

would it be s[10]=1(1-2^10)/(1-2) answer 1023
the second term is ar , and r = 2
so 2a = 1/2
a = 1/4

sum(10) = a(r^10 - 1)/(r-1)
= (1/4)(2^10 - 1)/(2-1)
= (1/4)(1023) = 1023/4 or 255.75