Jawabanmu

2014-05-18T21:59:44+07:00
A(r² - 1)/r-1 = 24
a (r+1)(r-1) = 24 (r-1)
a = 24 /(r+1)

a (r^4 -1) / r-1 = 240
24(r² + 1) (r² - 1) = 240(r + 1)(r - 1)
(r² + 1) (r² - 1) = 10 (r² - 1)
r² + 1 = 10
r² = 9
r = √9
r = 3

a = 24 /(r+1)
a = 24 / (3 + 1)
a = 24/4
a = 6


U5 = ar^n-1
     = 6.3^4
     = 6 . 81
     = 486        E




1 1 1