8; 4 S5-? 1,5; 3 S5-? В4=1\16 В5=1\64 S5-? q=-2/3 S4=65B1=?

1) b1=8,b2=4q=4/8=0,5S5=a1*(q^n-1)*5/q-1=8*(0,5^5-1)*5/0,5-1=77,52) b1=1,5.b2=3q=3/1,5=2S5=a1*(q^n-1)*5/q-1=1,5*(2^5-1)*5/2-1=232,5 В4=1\16В5=1\64q=1/64:1/16=1/4a1=a4/q^3=4S5=a1*(q^n-1)*5/q-1=4*(1/4^5-1)*5/1/4-1=-6