Which expression represents the value of the arithmetic series? What is the value of the arithmetic series?
a) (Sₙ = n/2(a₁ + aₙ)), Calculate the sum
b) (Sₙ = n/2(a₁ + aₙ)), Find the common difference
c) (Sₙ = n/2(a₁ + aₙ)), Find the number of terms
d) (Sₙ = n/2(a₁ + aₙ)), Determine the first term