How many four digit numbers can be made up of the four numbers 2345 without repetition? What is the sum of all these four digit numbers Come on - thank you

How many four digit numbers can be made up of the four numbers 2345 without repetition? What is the sum of all these four digit numbers Come on - thank you

This is a permutation problem in Mathematics: it can be composed of 4 × 3 × 2 × 1 = 24 numbers, and its summation method can be calculated as follows: on the thousandth place: as far as the number "2" is concerned, it has 3 × 2 × 1 = 6, six different numbers (2345 2354 2435 2453 2534 2543) and the other 2, 3 and 4 also have six numbers

1.2345＾2+（0.7655）＾2+2.469×0.7655-2.5＾2

=1.2345²+2×1.2345×0.7655+0.7655²-2.5²
=(1.2345+0.7655)²-6.25
=4-6.25
=-2.25

Finding the solution set of inequality 2 – X / x2 + 3x + 2 > 0

2–x/x2+3x+2>0
(x-2)/(x+1)(x+2)

If the area of a circle is equal to that of a square, what is the ratio of the circumference of a circle to that of a square?

Let the radius of the circle be r and the side length of the square be X. if the two areas are equal, the ratio of π R ^ 2 = x ^ 2 (√π) r = x circumference is 2 π R / 4x = root sign π / 2. What's the middle step? The area of the circle is π R ^ 2 square area X ^ 2 circle perimeter 2 π r square perimeter 4x is

The four numbers ABCD are not equal to each other, and ABCD = 25. Get the value of a + B + C + D

Because 25 = 5 * 5, it is unlikely that a, B, C, D are all positive numbers, because if they are all positive numbers, there are no more than two cases: 1. Two of them are 5, but the topic requirements are not equal to each other. 2. One of them is 25, but in this way, the other three numbers must all be 1

Write the coefficients of the following polynomials and the degree of each polynomial:
【1】 The second power of 3a-b [2] 3x-4x + the second power of 5Y [3] 2 / 2 x [4] 5 / 3x-4y

1, coefficient: 3, - 1, degree: 2
2, coefficient: 3, - 4,5, times: 2
3, coefficient: 1 / 2, - 1 / 2 times: 1
4, coefficient: 3 / 5, - 4 times: 1

CAD knows the two ends of arc, chord length and mid point arch height. What's the simplest way to make arc
In fact, the arc is made at three points, but because the arc is not horizontal, it is impossible to determine the coordinates of the highest point in the middle, but you know the arch height of the midpoint of the chord. How do you draw it

Connect 2 endpoints
Shortcut o key enter, input arch height, offset just connected line segment
Then draw an arc at three points, point the first endpoint in turn, the midpoint of the offset line segment, and the last endpoint
Capture settings: right click the capture icon at the bottom, and then select all in the capture panel settings. Basically, I select all. It's convenient for drawing. There's no need to set common capture points separately

CN = (2n + 1) 8 Λ (n-1) sum by dislocation subtraction method

letS =1.8^0+2.8^1+.+n.8^(n-1) (1)8S = 1.8^1+2.8^2+.+n.8^n (2)(2)-(1)7S = n.8^n -[1+8+...+8^(n-1) ]=n.8^n -(1/7)(8^n -1)S = (1/7)[ n.8^n -(1/7)(8^n -1) ]cn= (2n+1).8^(n-1)= 2[n.8^(n-1)] + 8^(n-1)Sn = c...

Is the solution of equation 6 △ 3x = 12 2x = 12, x = 6 or 3x = 6 △ 12, 3x = 1 / 2, x = 1 / 6?

The solution of 6 △ 3x = 12 is 2x = 12, x = 6
The solution of 6 △ (3x) = 12 is 3x = 1 / 2, x = 1 / 6

English translation
English composition for Spring Festival

Today I feel good,because the New Year will come next month.I rode a bike to the mall to buy stocking street is really busy,there are a lot of people are preparing the New Year with things.I also met ...