Question

A partial sum of an arithmetic sequence is given. Find the sum.
4 + 9 + 14 + . . . + 484 need help

Answer 1

The sum forumla you may find useful is
\[S_n = \frac{1}{2} \cdot n(a+l) \]

You just need to find the number of terms...

Answer 2

(Where a = first term, l = last term, n = number)

Answer 3

I cant find n though

Answer 4

Hint: The nth term = (n-1)d, so 484 = (n-1)*4 => n-1 = 484/4

Answer 5

sorry, not 4 :/

Answer 6

a+(n-1)d ***

Answer 7

=>484 = 4 + (n-1)*5

Answer 8

so n is 121. because 484/4= 121

Answer 9

No sorry I misread it, see the post below.

Answer 10

the post below??

Answer 11

a+(n-1)d
=>484 = 4 + (n-1)*5