Question

what is the sum of first n even natural number?

Answer 1

$\huge \: hi \: here \: is \: your \: answer \\ \\ the \: sum \: of \: first \: n \: numbers \: is \: \\ n(n + 1) \div 2$

Answer 2

Here,
(first term)a=2
(number of terms)=n

(common difference)d=2
therefore, sum of nth terms
Sn=n/2×(2a+(n-1)d)
Sn=n/2×{4+(n-1)2}
Sn=n/2×(4+2n-2)
Sn=n/2(2n+2)
Sn=n/2×2(n+1). {taking 2 common}
Sn=n(n+1)
Sn=n²+n
So, sum of nth terms is n²+n.