Write the sum of the series : 2 + 4 + 6 + 8 + ….. + 2n

Let S = 2 + 4 + 6 + 8 + ….. + 2n


S = 2(1 + 2 + 3 + 4 + ….. + n)



Substituting the above value



S = n(n + 1)


1