Answer:
18cot(30) or nearly -2,81016
The answer is root. Hope this helps!
3, 1, -1, -3, -5
-2 -2 -2 -2
a(n) = a₁ + d(n - 1)
a(n) = 3 - 2(n - 1)
a(n) = 3 - 2(n) + 2(1)
a(n) = 3 - 2n + 2
a(n) = -2n + 3 + 2
a(n) = -2n + 5
a₁₄ = -2(14) + 5
a₁₄ = -28 + 5
a₁₄ = -23
The answer is C.
Step-by-step explanation:
The sum of an arithmetic series is found by multiplying the number of terms times the average of the first and last terms. Example: 3 + 7 + 11 + 15 + ··· + 99 has a1 = 3 and d = 4.
