Final answer:
The marginal cost (MC) is calculated as the change in total cost divided by the change in quantity for a given quantity level.
Step-by-step explanation:
The marginal cost (MC) is calculated as the change in total cost divided by the change in quantity.
To find the marginal cost for the total cost function T C(q)=20+4 q+0.5 q², we need to calculate the change in total cost and the change in quantity at a given quantity level.
Let's take two quantity levels, q1 and q2. The change in total cost is TC(q2) - TC(q1), and the change in quantity is q2 - q1.
Once we calculate these values, we can determine the marginal cost by dividing the change in total cost by the change in quantity.