Question

Please help me out on this !!!

Answer 1

we are given

$\sum _{i=1}^8\:2^{i-1}$

we can expand it

$\sum _{i=1}^8\:2^{i-1}=2^{1-1}+2^{2-1}+2^{3-1}+2^{4-1}+2^{5-1}+2^{6-1}+2^{7-1}+2^{8-1}$

$\sum _{i=1}^8\:2^{i-1}=2^{0}+2^{1}+2^{2}+2^{3}+2^{4}+2^{5}+2^{6}+2^{7}$

we can simplify it

and we get

$\sum _{i=1}^8\:2^{i-1}=255$............Answer