Question

Tolong no.10 a & b dengan cara.......

Answer 1

U6=a.r^5=10/81
U4=a.r^3=10/9

r^2=1/9
r=1/3
---->a.(1/3)^3=10/9
                9a=27 x 10
                  a=30

U10=30.(1/3)^9=30.1/19683=1/656,1

Answer 2

U4 = 10/9
ar^3 = 10/9

ar^5= 10/81
ar^3 . r^2= 10/81
10/9 . r^2 = 10/81
         r^2 = 10/81 . 9/10
         r^2 = 9/81
         r^2 = 1/9
          r   = 1/3
ar^3 = 10/9
a. (1/3)^3 = 10/9
a. 1/27  = 10/9
a  = 10/9 . 27/1
a  = 30
 
ar^9 = 30 (1/3)^9
      = 30 . 1/19683
      = 0,001524

tolong di cek lagi ya...maaf kalo ada yang salah, ^_^