1
a)q=-6/4=-3/2
a3=-6*(-3/2)=9
a4=9*(-3/2)=-13,5
a5=-13,5*(-3/2)=20,25
b)q=2√6/2√2=√3
a3=2√6*√3=2√18=2*3√2=6√2
a4=6√2*√3=6√6
a5=6√6*√3=6√18=6*3√2=18√2
2
a18=a1+17d=5,6+17*0,6=5,6+10,2=15,8
3
q²=b3/b1=80/5=16
q=-4
S5=b1(1-q^5)/(1-q)
S5=5(1+1024)/(1+4)=5*1025/5=1025
q=5
S5=(1-1024)/(1-4)=5*1023/3=5*341=1705
4
d=-14-(-12)=-14+12=-2
B1
a1=37,a=2;an=113
37+2(n-1)=113
29n-1)=113-37
2(n-1)=76
n-1=76:2
n-1=38
n=38+1
n=39
a39=113
S39=(a1+a39)*39/2=(37+113)*39/2=150*39/2=75*39=2925
C1
a1=-10
a5=-810
q^4=a5/a1=810/10=81
q=-3
-10;30;-90;270;-810
q=3
-10;-30;-90;-270;-810