Short-term costs are all related to output, so we can get the curves of the relationship between these costs and output, that is, the cost curve, the average cost curve and the average variable cost curve first decline and then rise with the increase of output, that is, they are U-shaped.

1, the short-term average cost curve is u-shaped, because the marginal income decreases. The law of diminishing marginal income means that with the increasing input of a variable factor, the marginal products brought by it first increase, reach the maximum value and then decrease.

2. The short-term marginal cost curve is U-shaped, which is determined by the law of diminishing marginal income. Because this law is at work, with the increase of variable factors, the marginal product will increase first and then decrease, so the marginal cost will decrease first and then increase, and the result is that the marginal cost curve must be U-shaped.

Exhibition materials:

1, short-term average cost curve, a common term in the futures industry. Average total cost is equal to average variable cost plus average fixed cost, or equal to total cost divided by output. The average total cost of a certain output level is the slope of the straight line between the corresponding point and the origin on the total cost curve.

2. Short-term marginal cost refers to the total cost increase caused by the manufacturer per unit output in a short period of time.