For a positive integer

MATHEMATICS · Single correct · CBSE · Mathematics · Number Play · Number Play

Problem

n

, the value of

\displaystyle \sum_{k=1}^{n} k

is (a)

\dfrac{n(n-1)}{2}

(b)

\dfrac{n^{2}}{2}

(c)

\dfrac{n(n+1)}{2}

(d)

\dfrac{(n+1)(n+2)}{2}