prove-that-r-k-n-r-1-2-n-n-1-show-with-a-diagram-that-the-volume-of-a-parallepipe-is-a-b-c-

Question Number 66803 by Rio Michael last updated on 19/Aug/19

p r o v e t h a t

\underset{r = k}{\sum^{n}} r = \frac{1}{2} n (n + 1)

s h o w w i t h a d i a g r a m t h a t t h e v o l u m e o f a p a r a l l e p i p e i s a . (b \times c)

Commented by JDamian last updated on 19/Aug/19

D i d y o u m e a n “ r = 1^{″} ?

Commented by Rio Michael last updated on 20/Aug/19

y e s

Commented by Cmr 237 last updated on 20/Aug/19

v r a i m e n t

Answered by $@ty@m123 last updated on 20/Aug/19

S = 1 + 2 + 3 + \dots . . + n

a = 1, d = 1

S = \frac{n}{2} [2 a + (n - 1) d]

S = \frac{n}{2} [2 + n - 1]

S = \frac{1}{2} n (n + 1)