Question

Tentukan hasil 1+3+5+7+9+.....+99

Answer 1

Awal = 1
beda = 2

Un = a + (n-1)b
99 = 1 + (n-1)2
99 = 1 + 2n - 2
99 = 2n - 1
2n - 1 = 99
2n = 99 + 1
2n = 100
n = 100/2
n = 50

Sn = n/2 (a + Un)
= 50/2 (1 + 99)
= 25 (100)
= 2.500

Answer 2