Which of the following gives the sum of the first terms of an arithmetic progression…

MATHEMATICS · Single correct · CBSE · Mathematics · Arithmetic Progressions · Arithmetic Progressions

Problem

Which of the following gives the sum

S_n

of the first

n

terms of an arithmetic progression whose first term is

a

and common difference is

d

? (a)

n\bigl[a+(n-1)d\bigr]

(b)

\dfrac{n}{2}(a+d)

(c)

\dfrac{n}{2}\bigl[2a+(n-1)d\bigr]

(d)

\dfrac{n}{2}\bigl[2a+(n+1)d\bigr]