+118653 What is 1+2+4+6+8+10+................1000?
It is not a proper sequence but it looks like
1+ 2+4+6+8+10+................1000?
1+ an AP with a=2, d=2 and Last term=1000
\(Sum=1\;\;\;+\;\;\;\frac{n}{2}(a+L)\\ n=?\;\;\;a=2\;\;\;L=1000 \quad find \;\;n\\~\\ \quad t_n=a+(n-1)d\\ \quad1000=2+(n-1)*2\\ \quad1000=2n\\ \quad n=500\\~\\ Sum=1\;\;\;+\;\;\;\frac{500}{2}(2+1000)\\ Sum=1\;\;\;+\;\;\;250*(1002)\\\)
Sum = 1+250*1002 = 250501
Welcome to the Web2.0calc forum ant101 
