Barisan aritmatika Diketahui a=12 b=-5 n=11100 Hitung Un Dan Sn

a = 12
b = -5
n = 11100
U(n) = a + (n - 1)b
        = 12 + (11100 - 1)(-5)
        = 12 - 55500 + 5
        = 17 - 55500
        = -55483
S(n) = n/2(a + U(n))
        = 11100/2(12 - 55483)
        = 11100(-55471)/2
        = -307864050