Answer to Question #295948 in Microeconomics for Gees

Question

Every point on the long run average cost curve is a tangancy point with some short run marginal cost curve and that there are infinite number of short run marginal cost curves

Answer 1

In the long run, we usually have several marginal short run marginal cost curves obtained for the long run period. Short run marginal cost curves only deals with the Variable costs excluding Fixed costs. However, in the long run fixed costs also become variable costs. A marginal total cost curve including both fixed and variable costs will therefore be tangent with the several marginal cost curves obtained from the several short run periods.