Question

Hitunglah deret bil berikut.
A. 1+3+5+7+........+71.
B. 50+45+40+.......+15​

Answer 1

A = 1+3+5+7+...+71 = 1+3+5+7+...+65+67+69+71 = 37
= 72+72+72+...+72+71
= 37 x 72/2 + 71
= 37 x 36 + 71
= 1332 + 71 = 1403


B = 50+45+40+...+15 = 50+45+40+...25+20+15 = 8 bilangan
= 65 x 8/2
= 65 x 4 = 260
Misal kaalo salah, maaf ya