Find the sum of the first 27 terms
of the arithmetic sequence.
First, fill in the equation.
a₁
= 5 and a27
Sn = 2/(a₁ + an)
Sn
=
[?]
2
+
=
83

Answer:

S₂₇ = 1188

Step-by-step explanation:

using the given formula for [tex]S_{n}[/tex] , that is

[tex]S_{n}[/tex] = [tex]\frac{n}{2}[/tex] (a₁ + [tex]a_{n}[/tex] )

with a₁ = 5 and [tex]a_{n}[/tex] = a₂₇ = 83 , then

S₂₇ = [tex]\frac{27}{2}[/tex] (5 + 83) = 13.5 × 88 = 1188