1. Start with the utility function:
U(q) = -q^2 + 80q + 25,300
2. Find the first derivative of the utility function to identify the critical points:
\frac{dU}{dq} = -2q + 80
3. Set the first derivative equal to zero and solve for \( q \):
-2q + 80 = 0
-2q = -80
q = 40
4. To confirm that this critical point is a maximum, evaluate the second derivative:
\frac{d^2U}{dq^2} = -2
Since the second derivative is negative, \( U(q) \) has a maximum at \( q = 40 \).
5. Substitute \( q = 40 \) back into the utility function to find the maximum utility:
U(40) = -40^2 + 80 \cdot 40 + 25,300
U(40) = -1600 + 3200 + 25,300
U(40) = 1600 + 25,300
U(40)=26,900
6. Therefore, the maximum utility is:
U(q)=26,900