Question

the sum of series 4,0,-4,......100th terms is


it's answer is -19400.plz give me a method to solve this ​

Answer 1

Answer:

Find the sum:

∑k=150(3k+2)

First find a1 and a50 :

a1=3(1)+2=5a20=3(50)+2=152

Then find the sum:

Sk=k(a1 + ak)2S50=50(5 + 152)2=3925