Question

Hasil dari-100-99-98-....-2-1-0+1+2+....+97+98+99(tanpa menghitung satu persatu) adalah

Answer 1

Diketahui :
a = -100
U2 = -99
U3 = -98
Un = 99

Ditanya :
Sn?

Jawab :
b = U3 - U2 = U2 - a
b = -98 - (-99) = -99 - (-100)
b = 1

Un = a + (n - 1)b
99 = -100 + (n - 1)1
99 = -100 + n - 1
99 = -101 + n
n = 200

Sn = (a + Un)
S200 = (-100 + 99)
S200 = 100(-1)
S200 = -100