In the plane rectangular coordinate system, the coordinates of point a are (3, - 4), its symmetry about y axis, the coordinates of point B are (), △ OAB are () triangles

In the plane rectangular coordinate system, the coordinates of point a are (3, - 4), its symmetry about y axis, the coordinates of point B are (), △ OAB are () triangles

In the plane rectangular coordinate system, the coordinates of point a are (3, - 4), its symmetry about y axis, the coordinates of point B are (- 3, - 4), and △ OAB is (isosceles) triangle

Ellipse: x ^ + y ^ / 4 = 1, the left and right ends of the minor axis are a and B respectively, and the straight line L: y = KX + 1 intersects the X axis and Y axis with two points E and f respectively
Intersection with ellipse and two points c and D
1. If CF = FD, find the equation of line L
2. Let the slopes of the straight lines AD and CB be K1 and K2 respectively. If K1: K2 = 2:1, find the value of K

Excuse me: is there a problem with your topic?
The intersection of y = KX + 1 and Y axis is f (0,1); let C (x1, Y1); D (X2, Y2)
It is known from CF = FD that f is the midpoint of CD,
So X1 + x2 = 0
When the ellipse X & # 178; + Y & # 178 / 4 = 1 and the linear equation y = KX + 1 are eliminated, y is obtained
（4+k²)x²+2kx-3=0
From X1 + x2 = 0, we can get: k = 0; at this time, the line L: y = 1 has no intersection with the X axis, which is contradictory to the meaning of the topic;

2002+2004+2006+.+2050=?

Original formula = 2000 x 49 + (2 + 4 + 6 +...) +50)
Where (2 + 4 + 6 +...) +50) use the formula of arithmetic sequence
Sum of arithmetic sequence = (first term + last term) × number of terms △ 2
=(2+50)X25÷2=650
Among them, the number of items is the sum of several numbers, and we can find the law
Original formula = 2000 x 49 + (2 + 4 + 6 +...) +50)
=98000+650=98650

Simple calculation of 10.75 + 0.4-9.86

10.75+0.4-9.86
=10.75+0.4-(10-0.14)
=10.75+0.4-10+0.14
=(10.75-10)+(0.4+0.14)
=0.75+0.54
=1.29

I want to ask you a math problem. Xiaoming and I own a toy car together. It's 28 yuan, 14 yuan per person. But I have no money, so I borrow 14 yuan from Xiaohua (Xiaohua also wants to, so she agrees to be half of me). How much should I pay Xiaohua?
Help answer this question!

It's 14 yuan

Observe the following numbers: 1 / 1,3 / 4, - 5 / 7, - 7 / 10,9 / 13,11 / 16, - 13 / 19, - 15 / 22,17 / 25,... Answer the following questions according to the law:
1) What are the 16th and 33rd numbers in this column? (2) please use the algebraic expression of n to express the nth number a n
The last a n means: n is in the lower right corner of A

The 16th number is - 31 / 46, and the 33rd number is 65 / 97
An = (- 1) ^ [n (n + 1) / 2 + 1] * (2n-1) / (3n-2). N is 1,2,3 .
(- 1) ^ [n (n + 1) / 2 + 1] denotes the power n (n + 1) / 2 + 1 of - 1

If the maximum pressure a snow can bear is 2 times 10 to the third power PA, then if she wants to go skiing, what is the area of all the skis at least?

The detailed solution is as follows
Because the maximum pressure of snow is 2000Pa, the normal stress of snowboard should be less than 2000Pa to ensure safety
Normal stress σ = f / S (F is the pressure exerted by human body on skis, equal to Mg, s is the total area of skis, G is 9.8, approximate calculation can be 10)
The solution is s = f / σ = mg / σ = m * 9.8/2000
****The area is square meters!
Make the following supplementary explanation!
However, the calculated value at this time is a theoretical value! When you slide, there will be many factors, such as the change of snow carrying capacity, the inclination of the skateboard and so on, which will cause stress concentration (in short, the local pressure is too large), So divide the σ in the above formula by a factor greater than one to get [σ] (called safety stress or stress). Use this [σ] to recalculate the size of the sliding plate
But at the same time, we should also consider that the load-bearing capacity is greatly increased because the snow becomes dense after being compressed. So the actual situation is far more complicated than this theoretical result
At the same time to give you a reference: General ski resort, because of dense snow, its bearing capacity is almost equal to the general ground bearing capacity. As you said, 2KPa bearing capacity is impossible to ski

A cuboid container is 20 cm long and 10 cm wide. The height of the water in it is 8 cm. Pour these into a cuboid container with 20 cm long edges. What is the height of the water in square cm? (use the equation to solve)

Set the height as X
20*10*8=20*20*x
X = 4 (CM)

Fill in 2, 6, 10, 14, 18, 22 and 26 according to the rule_____ (item n)

4n-2

In life, which objects are about 1 square centimeter, 1 square decimeter, 1 square meter

One square centimeter - nail plate