Question

bn=128,q=2,n=7.Найдите b1 и sn

Answer 1

bn=b1×q^n-1; b6=b1×q^6; 128=b1×2^6;
128=128×b1; b1=1;
S7=1×(2^7-1)/2-1= 128-1=127;
ответ: b1=1; S7=127.