1. Select all the incorrect descriptions related to the production function. (1) The downward direction of the equivalent curve means that the limit technology substitution rate exists.

(2) When the total product is maximized, the average production is zero.

(3) The higher the degree of convexity of the equivalent curve to the origin, the lower the likelihood of substitution between components.

(4) At the equilibrium point where the equivalent curve and the equivalent cost curve meet, the company's profit margin is maximized.

(5) If a fixed input element exists, it is short-term.

2. Choose all the wrong answers for the cost.

(1) An increase in fixed costs in the short term reduces production. (2) When a monthly factory rent is incurred, the plant rent is a variable cost. (3) In an interval where marginal costs decrease, average costs must decrease. (4) The marginal cost must also increase in the interval in which the average cost increases. (5) An economy of scale is a case in which costs decrease as production increases.