Question

в геометрической прогрессии (Вn) В3=6, В5=8. Найдите В7

Answer 1

q^2=b5:b3, q^2=8:6= 4/3,  q1=-2/√3, q2=2/√3,

b1=b3:q^2, b1= 6: 4/3=9/2

b7=b1*q^6, b7=9/2*(2/√3)^6=9/2*64/81=32/9 

Answer 2

b7*b3=b5^2 b7=b5^2/b3=64/6=32/3