Economics topics, an economics question

If the nonlinear demand curve is concave, then the nonlinear marginal return curve is bisected by the distance between the **axis and the demand curve:

tr=pq=q*f(q)

mr=tr'=f(q)+q*f'(q)

Slope of mr = mr'=2f'(q)+q*f"(q)d=f(q)

Slope of d = f'(q)

then f"(q) <0, so choose c

You can also do this: let the demand curve be p=f(q),f''(q) <0 because the question says that the demand curve is concave. Then tr=pq=qf(q), then mr=f(q)+f'(q)q.

The slope of the demand curve is: f'(q), while the slope of the marginal return is: 2f'(q)+f''(q)。

And f''(q) <0, then you can know that it is on the right. Because the slope of the marginal return is a little smaller than twice the slope of the demand curve, it should be a little to the right in the middle.

The change in demand refers to the change in the demand for a commodity caused by the change of ** when other conditions remain unchanged. In geometry, the change in demand is expressed as the movement of the combination of demand quantities of a commodity along a given demand curve. For example, when a commodity changes from 2 yuan to 5 yuan, and the demand for the commodity it causes drops from 600 units to 300 units, the combination of the demand quantity of the commodity moves from point A along the established demand curve qd=f(p) to another point b.

Note that this change represents a change in the quantity of demand, but does not represent a change in the overall state of demand. Because of the change in demand, the points of change are all on the same demand curve.

What is often confused with changes in demand is changes in demand. The change in demand refers to the change in the demand for a commodity due to other factors under the condition that the commodity remains unchanged. Other factors here refer to changes in the level of consumer income, changes in related goods, changes in consumer preferences, and changes in consumer expectations for goods.

In geometry, a change in demand is represented by a shift in the position of the demand curve.

The diagram is not easy to do, let me tell you how to do it, just introduce it with the unary function image of junior high school, set the ice cream, the amount of lemonade is x1 and x2 respectively, and the cost is y1 and y2 respectively, then the function is:

x2=y2;So there are two straight lines, and then establish a coordinate system, draw the straight line, take the first quadrant, and then add a straight line parallel to the x-axis y=5 so that you can besiege a figure, and then according to the change of the figure you can draw the conclusion you want, what will not continue to ask.

There's no way to draw it here, but to give you an idea, it's about the shape of a mountain when you draw it.

1.From y=c+i, y=2500-25r (1) from m=l, derive, y=1500+25r (2) according to (1) and (2) get y=2000, r=20, and then find i=200, substitute l=, and obtain, l=304, l-m=304-300=4 is the additional investment.

In addition, there is no such thing as an exaggerated fiscal policy, but an expansionary fiscal policy.