Question

Tentukan empat suku pertama suatu barisan yg suku ke-n nya dinyatakan dgn
1/2n(n+1) =

Answer 1

U1 = 1/2 . 1 . (1+1) = 1/2 . 1 . (2) = 1
U2 = 1/2 . 2 . (2+1) = 1/2 . 2 . (3) = 3
U3 = 1/2 . 3 . (3+1) = 1/2 . 3 . (4) = 6
U4 = 1/2 . 4 . (4+1) = 1/2 . 4 . (5) = 10

Answer 2

U1 = 1/2 (1) (1+1) = 1
U2 = 1/2 (2) (2+1) = 1/2 (6) = 3
U3 = 1/2 (3) (3+1) = 1/2 (12) = 6
U4 = 1/2 (4) (4+1) = 1/2 (20) = 10