Due to the severe drought in the south, the storage capacity of Reservoir B continues to decrease at

This shouldn't be the whole topic, right?,That's it.** Calculated.。

1) The amount of water discharged by A can be calculated from the decrease of water in 5 days from the image of function A;

2) On the 10th day, the water from reservoir A will be injected into reservoir B.

Let the analytic formula of the straight line ab be: y=kx+b b(0,800),c(5,550).

b=800 5k+b=550

k=-50 b=800

The analytic formula of the straight line ab is: yab = -50 x + 800 when x = 10, y = 300 At this time, the water storage capacity of reservoir B is 300 (10,000 m3) 3) The water discharge per unit time of reservoir A is the same as the water inflow per unit time of reservoir B and the loss is not counted.

The intake time of reservoir B is 5 days.

The storage capacity of reservoir B after 15 days is: 300 + (3000-1000) - 50 5 = 2050 (10,000 m3).

a（0，300），d（15，2050）

Let the analytic formula of the straight line ab be: y=k1x+b1 10k1+b1=300 15k1+b1=2050

k1=350 b1=-3200

The analytic formula of the linear ad is: yad=350x-3200

Solution: (1) The daily discharge of reservoir A is (3000-1000) 5=400 (10,000 meters for 3 days).

2) On the 10th day, the water from reservoir A will be injected into reservoir B.

Let the analytic formula of the straight line ab be: y=kx+b b(0,800),c(5,550).

b=800 5k+b=550

k=-50 b=800

The analytic formula of the straight line ab is: yab = -50x+800

When x=10, y=300 The storage capacity of reservoir B is 300 (10,000 m3).

The storage capacity of reservoir B after 15 days is: 300 + (3000-1000) - 50 5 = 2050 (10,000 m3).

a（0，300），d（15，2050）

Let the analytic formula of the straight line ab be: y=k1x+b1 10k1+b1=300 15k1+b1=2050

k1=350 b1=-3200

The analytic formula of the linear ad is: yad=350x-3200

1) The amount of water discharged by A can be calculated from the decrease of water in 5 days from the image of function A;

2) It can be seen from the image that the water storage of reservoir B begins to increase after 10 days, and the coordinates of point A are obtained from the analytical formula of the function of the straight line ab, and the water storage capacity of reservoir B at this time is obtained.

3) The analytical formula of the linear AD requires the coordinates of point D, and the discharge volume of A is the water inflow of B, then the abscissa of D is 15, and the ordinate of D is 15 according to the equivalent relationship of "the water storage of B after 15 days = the original water volume of 10 days + the amount of water injected by A - the amount of water discharged by itself", and then the analytical formula of the function is obtained

The coordinates of point A in the third question should be (10,300), so that the analytic formula of the straight line ad can be calculated.

yad=350x-3200

1) The amount of water discharged by A can be calculated from the decrease of water in 5 days from the image of function A;

2) On the 10th day, the water from reservoir A will be injected into reservoir B.

Let the analytic formula of the straight line ab be: y=kx+b b(0,800),c(5,550).

b=800 5k+b=550

k=-50 b=800

The analytic formula of the straight line ab is: yab = -50x+800

When x=10, y=300 The storage capacity of reservoir B is 300 (10,000 m3).

3) The first liter of reservoir A has the same amount of water discharge per unit time as the water inflow per unit time of reservoir B, and the loss is not known.

The intake time of reservoir B is 5 days.

The storage capacity of reservoir B after 15 days is: 300 + (3000-1000) - 50 5 = 2050 (10,000 m3).

a（0，300），d（15，2050）

Let the analytic formula of the straight line ab be: y=k1x+b1 and Lu Lao 10k1+b1=300 15k1+b1=2050

k1=350 b1=-3200

The analytic formula of the linear ad is: yad=350x-3200

Solution: (1) The daily discharge of reservoir A is (3000-1000) 5=400 (10,000 meters for 3 days).

2) On the 10th day, the water exported from this base reservoir of water A will be injected into reservoir B.

Let the analytic formula of the straight line ab be: y=kx+b b(0,800),c(5,550).

b=800 5k+b=550

k=-50 b=800

The analytic formula of the straight line ab is: yab = -50x+800

When x=10, y=300 At this time, the storage capacity of reservoir B is 300 (10,000 m3).

The storage capacity of reservoir B after 15 days is: 300 + (3000-1000) - 50 5 = 2050 (10,000 m3).

A (0,300), d (15, row wheel 2050).

Let the analytic formula of the straight line ab be: y=k1x+b1 10k1+b1=300 15k1+b1=2050

k1=350 b1=-3200

The analytic formula of the linear ad is: yad=350x-3200

Solution: (1) From the meaning of the title, it is obtained: the daily discharge of reservoir A is (3000-1000) 5=400 (10,000 meters 3 days).

2) On the 10th day, the water from reservoir A will be injected into reservoir B.

Let the analytic formula of the straight line ab be: y=kx+b b(0,800),c(5,550).

Substituting the spike blindness, obtains: b=800 5k+b=550k=-50 b=800

The analytic formula of the straight line AB is: yab = -50 x + 800 When x = 10, the slow family and substitution get: the water storage capacity of reservoir B is 300 (10,000 m3) The water storage capacity of reservoir B after 15 days is:

300 + (3000-1000) -50 5 = 2050 (10,000 meters 3).

That is, a(0,300) and d(15,2050) let the analytic formula of the line ab be: y=k1x+b1

Substituting, obtain: 10k1 + b1 = 300 15k1 + b1 = 2050k1 = 350 b1 = -3200

The analytic formula of the straight line AD is: y=350x-3200, if you feel that the explanation is not detailed enough, you can still ask (but the basic steps have come out)!

Because A releases water for 5 days, B receives 5 days, and 50 is the amount of evaporation per day (800-550) 5=50

Solution: (1) The daily discharge of reservoir A is (3000-1000) 5=400 (10,000 meters for 3 days).

2) On the 10th day, the water from reservoir A will be injected into reservoir B.

Let the analytic formula of the straight line ab be: y=kx+b b(0,800),c(5,550).

b=800 5k+b=550

k=-50 b=800

The analytic formula of the straight line ab is: yab = -50x+800

When x=10, y=300 The storage capacity of reservoir B is 300 (10,000 m3).

The storage capacity of reservoir B after 15 days is: 300 + (3000-1000) - 50 5 = 2050 (10,000 m3).

a（0，300），d（15，2050）

Let the analytic formula of the straight line ab be: y=k1x+b1 10k1+b1=300 15k1+b1=2050

k1=350 b1=-3200

The analytic formula of the linear ad is: yad=350x-3200

The third question is incorrect, the coordinates of a should be (10,300).

Answer: Solution: (1) Let the function expression of the line segment bc be q kt b

The coordinates of points b and c are b(20,500) and c (40,600), respectively

Solution, k 5, b 400

The function expression for line segment bc is q 5t 400 (20 t 40).

2) The water supply rate of reservoir B is x10,000m3 h, and there is a drainage and irrigation gate of reservoir A.

The irrigation rate is y0,000 m3 h

Answer: The water supply rate of reservoir B is 150,000 m3 h, and the irrigation of a drainage and irrigation gate of reservoir A.

The irrigation rate is 100,000 m3 h

3) Because the minimum normal water level is a 500 15 20 200 (10,000 m3 h), (400 200) (2 10) 10 (h).

Answer: After 10 hours, the storage capacity of the reservoir dropped to the lowest value of the normal water level

Idea analysis: test center anatomy: This question examines the use of a function to solve practical problems, this kind of question is a hot problem in the high school entrance examination in recent years Note that when using a function to find the maximum value, the key is to apply the properties of the primary function; That is, the maximum value is determined by the change of the function q with t, combined with the range of the value of the independent variable

Solution: According to the coordinates of point B and point C, the analytical formula of line segment BC is determined by using the undetermined coefficient method. According to the relationship between the discharge water, the system of equations is listed to calculate the rate of water supply and irrigation and drainage of the two reservoirs.

Summary of rules: When finding the analytic formula of the function, the coordinates of two pairs of values or two points can be found through the image of the function, and the analytic formula of the line segment can be found by using the undetermined coefficients.

Example 8 In the summer of 2009, due to the continuous high temperature and the lack of rain, the storage capacity of the reservoir generally declined, Figure 11 29 is the relationship between the storage capacity v (10,000 m2) and the drought duration t (day) of a reservoir

1) How much is the original storage capacity of the reservoir in 10,000 m2? After 10 days of continuous drought, how many million meters of water will the reservoir hold?

2) If the storage capacity of the water bank is less than 4 million m3, a severe drought warning will be issued, may I ask: How many days after a continuous drought will a severe drought warning occur?

3) According to this law, how many days of drought will the reservoir dry up?

Analysis: From the function image, it can be seen that the functional relationship between the reservoir storage value (10,000 m2) and the drought time t (day) is a one-time function, and the analytical formula of the one-time function is v=kt+b (k, b is a constant, and k≠0)The analytic formula of this function can be obtained from the image, and then the questions (1), (2), and (3) of this question can be obtained

Solution: The functional relationship between the storage capacity v (10,000 m3) of the reservoir and the drought time t (day) is.

v=kt+b (k,b is a constant, and k=0).

As can be seen from the image, when t=10, v=800;When t=30, v=400

Substitute them into v=kt+b, get.

So v=-20t+1000(0 t 50).

1) When t=0, v=-20 0+1000=1000 (10,000 m2); When t=10, v=-20 10+1000=800 (10,000 m3) So the original storage capacity of the reservoir was 10 million m3, and after 10 days of continuous drought, the storage capacity of the reservoir was 8 million m3

2) When V 400, there is -20T+1000 400, so T 30, so when the drought continues for 30 days, a severe drought warning will occur

3) When v=0, there is -20t+1000=0, then t 50, so according to this law, when the drought lasts for 50 days, the reservoir will dry up

Note: The key to solving this problem is to find the functional relationship between v and t.

t=0，v=1200

t=50,v=200

It's a straight line, so v=kt+b

Substituting 1200 = 0+b

200=50k+b

b=1200,k=-20

v=-20t+1200

then t=10, v=-20*10+1200=10 million m v=-20t+1200<400

20t>1200-400=800

t>800/20=40

So in 40 days there will be a severe drought warning.

Solution: If the total amount of water is y,000,000 tons·km, there are y 50x 30 (14 x) 60 (15 x) 45 (x 1) 5x 1275

14 x 0, 15 x 0, x 1 0 1 x 14 y increases with x 1, y minimum 5 1 1275 1280 (10,000 tons·km).

The transportation plan is: 10,000 tons of water from A to A and 130,000 tons of water to B140,000 tons of water were transferred from B to A, and the minimum water transfer was 12.8 million tons·km.

(1) There are two ideas for completing **: from the perspective of supply or demand, the above table can be completed.

2) Use the formula (weight of water and distance of water) total volume = total volume of a + total amount of water of b and distance of water.

y=50x+(14 x)30+60(15x)+(x 1)45=5x+1275 (Note: the maximum value of a primary function should obtain the value range of the independent variable) 5 0 y increases with the increase of x, and if y is the smallest, x should be the largest.

1 x 14 from the solution

y=5x+1275 5 0 y increases with the increase of x, y should be the smallest then x should be the minimum = 1

The transportation plan is 1 ton from A to A and 13 tons to B;B to transfer 14 tons to A, not to B.

Answer] (left to right, top to bottom) 14 x 15 x x 1 y=50x+(14x)30+60(15x)+(x 1)45=5x+1275

Solve inequality 1 x 14

So when x=1, y obtains the minimum value.

y=5+1275=1280

The transportation plan is 1 ton from A to A and 13 tons to B;B to transfer 14 tons to A, not to B.