Question

Tentukan rumus suku ke n
1,4,16,24,...
5,10,20,40,...
9,27,81,243,...

Answer 1

Rumus : a r^(n-1)
            r = u2/a = ar^2/a
1,4,16,24  
r=4/1=4
ar^(n-1)
1 x  4 ^(n-1)
suku ke n = 4^(n-1)

5.10.20.40 (pakai cara sama dg diatas)
suku ke n = 5 x 2^(n-1)

9,27,81
r=27/9=3
suku ke n = 9 x 3^(n-1)
            = 3^2 x 3^(n-1)
              = 3^(n+1)