find the arithmetic mean A_n-1_-3.9, A_n+1_=7.1
To find the arithmetic mean between two numbers, you need to add the two numbers together and divide the result by 2.
In this case, the two numbers are Aₙ₋₁ = -3.9 and Aₙ₊₁ = 7.1.
To find the arithmetic mean, we need to add these two numbers together and divide the result by 2:
Aₙ = (Aₙ₋₁ + Aₙ₊₁)/2
Substituting the values:
Aₙ = (-3.9 + 7.1)/2
Now, we can calculate the arithmetic mean:
Aₙ = 3.2/2
Aₙ = 1.6
Therefore, the arithmetic mean between Aₙ₋₁ = -3.9 and Aₙ₊₁ = 7.1 is Aₙ = 1.6.