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How to calculate log3
What does 3 mean?
If it is to the third power, then
Original formula = [log 3 ^ (- 0.25)] ^ 3
If it is a base, then
Original formula = 0.25 * log 3 (27) - log 3 (3) = 0.75-1 = -0.25
Median algorithm of data statistics
For example, in order to mobilize the enthusiasm of the salesmen, the clothing department of a shopping mall decided to implement target management, that is, to determine the sales target of a month, and to give appropriate rewards and punishments to the salesmen according to the completion of the target. In order to determine an appropriate target, the shopping mall counted the sales of 30 salesmen in a month as follows: (unit: 10000 yuan)
17 18 16 13 24 15 28 26 18 19
22 17 16 19 32 30 16 14 15 26
15 32 23 17 15 15 28 28 16 19
What's the median
Is the algorithm to multiply the frequency of all data with the real number, and then sort out the real number of the middle data, that is, 180000 yuan
The median algorithm of this problem should be to rearrange the data from small to large. N is the number of samples, where the number of samples is 30. It is even
Then the sample median M = 1 / 2 [(x (15) + X (15 + 1)]
Here is m = 1 / 2 [x (30 / 2) + X (30 / 2 + 1)]
Where x is followed by a subscript in parentheses. I can't show it from above. So the result is m = 1 / 2 (18 + 18) = 18
Do you understand?
The calculation of median is mainly sorting, and then according to whether the number of samples is odd or even, determine the formula and substitute it into the formula to find the median
Xiaoma is solving the equation 2x − 13 = x + A2 − 1. When the denominator is removed, the - 1 on the right side of the equation forgets to multiply by 6, so the solution is x = 2. Try to find the value of a and correctly solve the equation
According to Ma's solution, the equation after removing denominator is: 2 (2x-1) = 3 (x + a) - 1, that is, x = 3A + 1, ∵ x = 2, ∵ 3A + 1 = 2, the solution is a = 13; after removing denominator, 2 (2x-1) = 3 (x + a) - 6, removing bracket, 4x-2 = 3x + 3a-6, moving term, 4x-3x = 3a-6 + 2, combining similar terms, x = 3a-4, a = 13
A factory uses the rectangular and square cardboard as shown in figure a to make the vertical and horizontal cuboid paperboard as shown in Figure B______ (1) there are 162 square cardboard and 340 rectangular cardboard. If you want to make 100 cartons of two kinds, set up x vertical cartons. ① according to the title, complete the following table: carton cardboard vertical cartons horizontal cartons square cardboard 2 (100-x); Rectangular paperboard (sheet) & nbsp; & nbsp; & nbsp; & nbsp; 4x ② according to the number of production of two kinds of cartons, what are the production plans? (2) If 162 pieces of square paper and a piece of rectangular paperboard are made into the above two kinds of cartons, the paperboard is just used up. It is known that 290 < a < 306. Find the value of A
(1) (1) as shown in the table: carton cardboard vertical carton horizontal carton square cardboard 2 rectangular cardboard 4x 3 (100-x) ② from the meaning of the question, x + 2 (100 − x) ≤ 1624x + 3 (100 − x) ≤ 340, the solution is 38 ≤ x ≤ 40. Also ∵ x is an integer, ∵ x = 38, 39, 40. Answer: there are three programs: production of 38 vertical cartons, 62 horizontal cartons; production of 39 vertical cartons, 61 horizontal cartons; production of 40 vertical cartons, 60 horizontal cartons; (2) if x vertical cartons are set, x square cartons are needed The equation system x + 2Y = 1624x + 3Y = a can be obtained, so we can get y = 648 − A5, because we know the value range of a is 290 ＜ a ＜ 306, so 68.4 ＜ y ＜ 71.6, take positive integer from y, then a = 298 when y = 70, a = 303 when y = 69, a = 293.293 or 298 or 303 when y = 71（ Write one of them
1. It costs 50 yuan to buy two chairs and one desk. It costs 25 yuan more to buy four chairs than one desk. What's the unit price of one desk and one chair?
2. In order to alleviate the drought, a reservoir has to deliver water to both a and B. the water demand of a is 1.44 million cubic meters, and that of B is 1.5 million cubic meters. Now, the water is delivered twice. The first time is to deliver water to a for three days and to B for two days, with a total of 840000 cubic meters; the second time is to deliver water to a for two days and to B for three days, with a total of 810000 cubic meters, Q: how many days will it take to complete the task of water supply to area a? How many days will it take to complete the task of water supply to area B?
3. It costs 420 yuan to buy 3 kg tea and 4 kg sugar. The same 2 kg tea costs 130 yuan more than 4 kg sugar. How much is the difference between each kg tea and each kg sugar?
What's the formula
1,2x + y = 50,4x-y = 25, x = 12.5, y = 25, table 25 yuan, chair 12.5 yuan
2. The water supply of site a is x 10000 cubic meters per day, and that of site B is y 10000 cubic meters per day
Then 3x + 2Y = 84,2x + 3Y = 81, x = 18, y = 15,
At this time, land X has water 5 * 18 = 900000, and land y has water 5 * 15 = 750000, so land a needs (144-90) / 18 = 3 days
It will take (150-75) / 15 = 5 days for B site
3,3x + 4Y = 420,2x-4y = 130, x = 110, y = 22.5,
X-Y = 87.5 yuan, the difference is 87.5 yuan
Use 2.7.0.5.1. These five numbers to form a five digit number. What is the minimum number equal to 30000 and what is the maximum number equal to 70000
Minimum 25017, maximum 75210
Mathematics problems in grade one of junior high school are in urgent need
1. The known wind speed is 10km / h, and the flight speed of the aircraft is 1250km / h when there is no wind, then the flight speed of the aircraft is () km / h when it is windward
2. If a two digit number, ten digit number is x, and one digit number is three times less than two times of ten digit number, then the two digit number is ()
1. The known wind speed is 10km / h, and the flight speed of the aircraft is 1250km / h in the absence of wind, then the flight speed of the aircraft in the downwind is (1250 + 10 = 1260) km / h
2. If a two digit, ten digit is x, and one digit is less than two times of ten digit, then the two digit is (10x + (2x-3) = 8x-3)
1+2+3+4+5+6+7+8+9+10+11…… +What is 1001 + 1002?
1000-2 = 998 998 means there are 998 numbers
998 divided by 2 = 499 499 1000
499X1000=499000
499000+500+1000+1001+1002=502503
If x + 2Y = y + 3Z = Z + 5x, then x ∶ y ∶ Z
x＋2y＝y＋3z＝z＋5x,
y=3z-x=5x-2z
z=1.2x
y=2.6x
x:y:z=1:2.6:1.2=5:13:6
What's the role of characters in serial paintings
Elaborate the content of the picture
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