Question 865202
r=1/2
S=t*(1 - r^n)/(1 - r)
S10=-8*(1 - 1/2^10)/(1 - 1/2)
S10=-1023/64 

Tn = t * r^(n - 1)
T = -8 * 1/2^(9)
T10=-1/64