tentukan hasil dari (tanpa menghitung satu persatu)

a]
1,3,5,7,...,99
n = (Un - a)/b + 1
n = (99-1)/(3-1) + 1
n = 50

Sn = (n/2)(a + Un)
S50 = (50/2)(1 + 99)
S50 = 2500

b]
(1-2)+(3-4)+...+(99-100)
= (-1) × 100/2
= -50

c]
-100 - 99 - ... - 1 + 0 + 1 + ... + 50
= -100 - 99 - .. - 51
= -(51 + 52 + ... + 100)
= -(50/2)(51 + 100)
= -3775