Question

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

Answer 1

U1 = a = 1
b = U2 - U1 = 3-1 = 2
n = 99

rumus jumlah suku :
Sn = n/2 x (2xa + (n-1)) x b
maka :
S99 = 99/2 x (2x1 + (99-1)) x 2
= 99/2 x (2 + 98) x 2
= 99/2 x 100 x 2
= 9900