Question

Помогите пж. ГП b1=16 , q=1/2 S8-?

Answer 1

Sn=b1(q^n -1) /(q-1) 

S8=16* ((1/2)^8 - 1) / 1/2-1 = 16*( 256-1) / -1/2 = -32*255 = - 8160