التكلفة الحدية من دالة التكلفة الكلية

In this video, we find marginal cost from a total cost function.

Consider question one. Total cost is T C equals one hundred plus five Q plus Q squared. Find the marginal cost at Q equals ten.

Marginal cost is the derivative of total cost with respect to output.

The constant contributes zero, five Q contributes five, and Q squared contributes two Q. So marginal cost equals five plus two Q.

At Q equals ten, marginal cost equals five plus two times ten, giving twenty-five.

Notice that fixed cost does not affect marginal cost. Hence, marginal cost at ten units of output is twenty-five cost units per additional unit of output.