Question

Sum of series: S = 1+2+3+4+…n

Answer 1

Answer:

Sum of n terms is

n(n+1)/2

.......!!

Answer 2

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$\huge\star\red{Given}$

S = 1+2+3+4+…n

$\huge\blue\star{solution}$

a=1,d=1,n=n

so by using this formula

sn=n/2[2a+(n-1)d]

sn=n/2[2×1+(n-1)1]

sn=n/2[2+n-1]

=n(n+1)/2

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