It is known that the weight of adult fish is 2 (1+x) 360 = 2000 (g) when d=360.
Therefore, x =1000 (1/360)-1.
Then the weight of each fish after d is w = 0.002 (1000 (1/360)) d (kg).
It is known that the feed consumption per kilogram of Yu Ri is 0.2*0.05=0.0 1 (yuan),
Then the feed price consumed by each fish in d days is c = ∑ 0.01* 0.002 (1+x) i (yuan), where I = 0. 1, 2, ..., d.
Knowing the selling price of fish, we can know that the average daily profit of each fish for d days is: (w*p-c)/d (yuan).
According to the calculation of substitution method, it can be seen that the daily average profit of each fish sold after 360 days of culture is the highest, so each fish should be completely raised to adult fish.
Therefore, the profit of each fish is 1 0 * 2-∑ 0.01* 0.002 (1+x) I (yuan), where i=0,1,2, ..., 360, which is approximately equal to/.
It is known that the pond is 1 00 *100 =10000 (square meters), and each square meter holds fish1kg. Fish can grow all year round, and the weight of daily growth is directly proportional to its own weight.
Therefore, as many fish as possible should be kept in the pond for as long as possible (the total weight should be slightly less than 10000Kg), and all the fish should be fished out on the last day, so that the number of fish put in and fished out every day should be the same. In the last 359 days,
No more fry are added to keep the same batch of 5000 fry in the pond.
Then, the first fish will come out on the 360th day, and the pond should be saturated at this time. Finally, 5000 fish will be produced in 1 day, which is 10000Kg adult fish.
If T-tail fry is released every day in the early stage, there will be 360 t ∑ 0.002 (1 000 (1/360)) I ≤10000 kg on the 360th day, where I = 1,12.
The specific plan and profit of three-year breeding are as follows:
Feeding 95 fry every day from day 65438 to day 359;
From the 360th day to the 735th day, 95 fry were fed every day, and 95 2Kg adult fish were taken;
On the 736th day, 5000 fry were fed, and 95 adult fish of 2Kg were taken.
From day 737 to day 1094, 95 2Kg adult fish were fed and taken every day;
On Day 1095, 5000 adult fish were taken from 2Kg, and call it a day!
* * * Obtained 74,825 adult fish of 2Kg, accounting for149,650kg, and gross profit/kloc-0 1494600.00 yuan.
It is not difficult to get the total feed price for three years: 77 167.50 yuan, then the maximum net profit is 14 19332.50 yuan!
The attached figure shows the variation curve of cumulative total mantissa and total weight in the three-year 1095-day breeding scheme.
Supplement: There seems to be room before 360 days, that is, more fry can be put in the early stage and sold within the range of 240 days to 359 days, that is, 0.2~2.0Kg, which can be found from the performance observation of the blue line in the figure. I am a poor math student, and I am not a professional student, so I will not calculate any more. Anyway, the landlord should be a math major and should be able to continue solving.
I'm glad to answer the landlord's question. Please forgive me if there is any mistake.