Please answer a question and write an analysis Thank you

Jingmen City (Jingmen, 2012) is known as the "Land of Fish and Rice". The wholesale distributor of the lake aquaculture farm purchased a total of 75 kilograms of grass carp and mullet (commonly known as black fish) and more than 40 kilograms of mullet in the mayor of Jingmen City. The wholesale unit price of grass carp is 8 yuan kg, the wholesale unit of ** and the function of the purchase amount of mullet.

1) Please write? The function of the total amount (10,000 yuan) (kg) and the purchase between the style required for wholesale market purchases, mullet.

2) If the dealer buys retail, grass carp and mullet can be sold for 89 ?95, so that the total retail volume is not less than 93 purchases, should be purchased from dealers at the lowest cost? What is the minimum fee?

Test Topic: An application of a linear function.

Analysis: (1) On the basis of the total requirement of the purchase of **, multiplied by y (yuan), you can write a function to parse (2) the unequal relationship between the total volume of purchases based on the total volume of purchases of not less than 93 can be x, and the inequality of purchases within x**. The cost can be expressed as a function of x, which can be based on the increase or decrease in functionality, the cost is found to be the minimum.

A: Solution: (1) Y (yuan) The function between the total amount and the purchase amount x (kg) y = 26 times the wholesale market purchase, mullet (20 x 40) 24x (x> 40).

2) Establish a dealer of mullet x kg to buy grass carp (75-x) kg, stocking at your own expense, w$.

The question of meaning is: x> 4089 (75-x)+95 93 75.

Solve x 50.

Watts = 8 (75-x) 24 = 16 times the meaning of 600 questions.

16> 0, w value? X's? Increase.

When x = 50, 75-x = 25, when w = 1400 (minimum).

A: The minimum cost of the purchase cost of dealers to purchase 25 kg, 50 kg, grass carp and mullet is 1400 yuan.

Comment: This question examines the properties, functions, properties of the function of time, the maximum value of the function, and the key is to obtain the range of x correctly.

Solution: (1) The functional relationship between the total amount of mullet required for wholesale purchase y (yuan) and the purchase amount x (kg) y=26x(20 x 40)24x(x 40)​

2) If the dealer buys x kg of mullet, then purchases grass carp (75-x) kg, and the required purchase cost is w yuan

Meaning from the title: x 4089% (75-x)+95% x 93% 75Solve x 50

From the inscription, w=8(75-x)+24x=16x+600 16 0, the value of w increases with the increase of x

When x=50, 75-x=25, W min=1400 (yuan) Answer: The dealer should buy 25 kg of grass carp and 50 kg of mullet to make the purchase cost the lowest, and the minimum cost is 1400 yuan

According to, root number = - root number.

I learned that only a number 0 could meet the condition.

Get x+y=2019

Solving the system of equations is obtained by +.

5x+5y+1+m=0

Substitute x+y=2019.

Get 5 2019 + 1 + m = 0

m=-10096

Convert the integration order first, and then integrate, and the result is 1 4-e to the power of -4.

When u2 = 0, n2 is considered a short circuit. Hence i2 = i1.

When U1 = 0, N1 is considered to be short-circuited, R1 and R2 are connected in parallel, and the current on R2 is I1R1 R2. So i2 = i1 + ir2 = i1 + i1r1 r2 = i1(1 + r1 r2).