Carilah kelima suku pertama dari soal ini Un = 1/2 x (n^2 - 1) Nb : ^ itu pangkat

Materi : Barisan dan deret

Pembahasan :
Un = 1/2 (n² - 1)

U1 = 1/2(1² - 1) = 0
U2 = 1/2(2² - 1) = 3/2
U3 = 1/2(3² - 1) = 4
U4 = 1/2(4² - 1) = 15/2
U5 = 1/2(5² - 1) = 12

Maka 5 Suku pertama :
0 , 3/2 , 4 , 15/2 , 12

Bab Barisan dan Deret
Matematika SMP Kelas VIII

Un = (1/2) x (n² - 1)

U1 = (1/2) x (1 - 1)
      = (1/2) x 0
      = 0

U2 = (1/2) x (2² - 1)
      = (1/2) x (4 - 1)
      = 3/2

U3 = (1/2) x (3² - 1)
      = (1/2) x (9 - 1)
      = 4

U4 = (1/2) x (4² - 1)
     = (1/2) x (16 - 1)
     = 15/2

U5 = (1/2) x (5² - 1)
     = (1/2) x (25 - 1)
     = 12

HP = { 0, 3/2, 4, 15/2, 12 }