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It is known that the square ABCD, AC is the diagonal of the square, through the D point, make de parallel AC to the upper left, connect EC to make the angle ace = 30 degrees, CE and ad intersect F, connect AE. Verification: AE = AF
As long as AC = EC is proved, AE = AF can be proved. Draw a auxiliary square dchg of the same size on the right to connect EG.CG.DH We can see that CED = 30 degrees, ED.DH On the same line. ED is perpendicular to CG, then CG = EC, because CG is also the diagonal of a square, so AC = CG, so AC = EC, so the triangle AEC is equilateral three
One plane is flying northeast at the speed of 800 km / h, and the other is flying 30 degrees north by West from the same place at the speed of 1000 km / h. how many km are the two planes apart in two hours?
Square 1: establish a coordinate system, using orthogonal decomposition method
Square 2: calculate the relative speed of the two aircraft
V = root (800 ^ 2 + 1000 ^ 2-2 * 800 * 1000 * cos75) = 1107.2
S=vt=2v=2214.4
Let K be a constant, and simplify the formula of Y
It is known that K is a constant, and the formula for y is reduced to 4Y + 3 [KY & # 178; - 2 (2Y & # 178; - 3Y) - 5 (Y & # 178; = 2y-3)] - 4 (1-2y). When k is a value, the value of this algebraic formula has nothing to do with the value of Y?
The original formula = 4Y + 3ky & # 178; - 12Y & # 178; + 18y-15y & # 178; - 30y + 45-4 + 8y = (3k-27) y & # 178; + 41; so when k = 9, the original formula = 41
If even function f (x) monotonically decreases on (negative infinity, 0), then inequality f (- 1)
Because f (x) is an even function and decreases monotonically on (- ∞, 0), f (x) increases monotonically on (0, + ∞)
Because f (- 1) 1
lgx1
So 0
The ratio of the original number of people in workshop a and workshop B is 4:3. When 48 people are transferred from workshop a to workshop B, the ratio of the number of people in workshop a and workshop B is 2:3. How many people are there in each workshop?
There are 4x and 3x people in each workshop
(4x-48)/(3x+48)=2/3
Solution
x=40
Then there are 40 * 4 = 160 and 40 * 3 = 120 people in each workshop
Move a matchstick, 123 + 123 = 1
How to move one of the matchsticks to make the equation hold
Just move the vertical part of the plus sign to the equal sign and change the equal sign to the unequal sign; since 123-123 ≠ 1
Junior one mathematics, calculation problems and simplification problems to detailed process, thank you, urgent
1、（1）2/-m+3/m=（） （2）（4/m+3）+(m-1/m+3)
2. The result of simplifying (X & # 178 / Y-X) - (Y & # 178 / Y-X) is ()
A、-x-y B、y-x C、x-y D、x+y
3. Calculation
（1）（x/x-2）-（2/x-2） （2）(x+5y/x+y)+(x-3y/x+y) (3)[x²-y/（x-3）²]-[9-y/（3-x）²] （4）（a²-1/a²-2a）+（4a-5/2a-a²） （5）（9m²/-3m-n）+（n²/n+3m）
4. Simplification: [A & # 178; - B & # 178; / (a-b) (A-C)] + [C & # 178; - B & # 178; / (a-b) (C-A)]
5. Simplification: (X & # 178; + X / X & # 178; - 1) - (x + 1 / x-1)
Note: here / all indicate the score line, each question at least 2. Thank you
1. The results of (1) 2 / - M + 3 / M = (1 / M) (2) (4 / M + 3) + (m-1 / M + 3) = 12, simplifying (X & # 178 / / Y-X) - (Y & # 178 / / Y-X) are (a) a, - X-Y B, Y-X C, X-Y D, x + Y3, calculating (1) (x / X-2) - (2 / X-2) & nbsp; = (X-2) / (X-2) = 1 & nbsp; (2) (x + 5Y / x + y)
1 2 3 4 5 6 7 8 9 10 100 1000
No, I mean love
It means:
Wholeheartedly
satisfy both sides
be of two minds
lead in all directions
all corners of the country
be puzzled
an unsettled state of mind
be all things to all men
a drop in the bucket
perfect
One in a hundred
that was a close call
Ten thousand horses galloping
13 times of a number plus 120 is exactly 18 times of this number. What's the number
120/（18-13）=24
Translation from English to Chinese
Your school is taking part in a project to help people.Add some more items to the poster.Then Talk about what you will do if you go to the project "we can help!"!
What do you mean by taking, part and in?
Your school is participating in an activity to help people. Add some items to the poster students, and then talk about what you would do if you went to the "I can help" activity
Taking part in is a fixed collocation
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