Question

Write the following arithmetic series in summation notation.
7+9+11+ . . . +35
..

Answer 1

Answer:

$S_{n}=315$

Step-by-step explanation:

$a_{1}=7\\a_{2}=9\\a_{n}=35$

d=9-7=2

no of terms n,

$n=\frac{a_{n-a_{1}} }{d} +1$

$n=\frac{{35}-{7}}{2} +1$

$n=15$

sum of series,

$S_{n}=\frac{n}{2} (a_{1}+a_{n})\\\\S_{n}=\frac{15}{2} (7+35})\\\\S_{n}=315$