Question

Tulislah rumus suku ke-n dari setiap barisan
1. 4, 8, 16, 32, ...
2. 9, 16, 25, 36 ,....
3. 1 * 2,2 * 3,3 * 4,4 * 5
4. 1/2 , 2/3, 3/4, 4/5, 5/6 ...
5. 1 , 1/4, 1/9, 1/16, 1/25 ,....

Answer 1

1. u1 = a = 4
r = 8/4 = 2
un = ar^(n-1)
Un = 4x 2^(n-1)
Un = 2^2 x 2^(n-1)
Un = 2^(n+1)
2. u1 = 9 = 3^2
U2 = 16 = 4^2
Un = (n+2)^2
3. Un = n(n+1)
4. Un = n/(n+1)
5. Un = 1/(n)^2