ответ: b1 = 2 ; b5= 1/8
Пошаговое объяснение:
S5= (b1*(q^5-1)) /q-1
3 7/8 = (b1*(1/2))^5-1)) /1/2-1
3 7/8 = (b1*(1/32-1)) /(- 1/2)
3 7/8 = (b1* (-31/32) /(- 1/2)
b1= 3 7/8 * (- 1/2)) /(-31/32)
b1 = 31/8*(-1/2)/ (-31/32)
b1 = -31/16/( -31/32)
b1 = -31/16 * (-32/31)= 2
b5= b1 * q^4= 2 * (1/2)^4= 2 * 1/16= 1/8
