Question

Sum of first n position intrger

Answer 1

Answer:

1.... .. ......... . . ..

Answer 2

Answer:

Step-by-step explanation:

→ 1+n=n+1  

→ 2+(n−1)=n+1  

→ 3+(n−2)=n+1

→ (n−1)+2=n+1  

→ n+1=n+1

→ On the left we are adding one number that scans 1 through n to another number that scans the same range backwards. On the right we always have n+1.  

→ Adding up all those equations we get the sum of the numbers 1 through n twice on the left, and n(n+1) on the right. So,

→ 1+2+3+…+n=n(n+1)2