Express the series using sigma notation. 5 + 8 + 11 + 14 +

So we see that each term is 3 more than the previous
so
we start with an=a1+d(n-1)
an=nth term
a1=first term
d=common difference
n=which term

first term is 5 and common differnce is 3
an=5+3(n-1)
an=5+3n-3
an=2+3n

so

ok, sigma notation

n=index of summation
a=first value of n
b=last value of n
and f(n) is the formula for the terms
so

the formula is 2+3n
the first value is 1
the last is ∞
so
represents the series