In the plane rectangular coordinate system xoy, given the point P (- 2,1), the point q is a moving point in the coordinate system. When the triangle poq is an isosceles triangle, the coordinates of point q are obtained

In the plane rectangular coordinate system xoy, given the point P (- 2,1), the point q is a moving point in the coordinate system. When the triangle poq is an isosceles triangle, the coordinates of point q are obtained

There are eight such points on the coordinate axis

1. Simple calculation of the third problem

1. 3x-1 / 12 = 2 / 15
3x = 2 / 15 + 1 / 12
3X=13/60
x=13/180
2. 4X of 5-1 of 5 = 3 of 8
4X of 5 = 3 of 8 + 1 of 5
4X / 5 = 23 / 40
x=23/40*5/4
x=23/32
3. 2 / 3 divided by [1-2 / 5 divided by 3 / 5]
=2 / 3 △ [2 / 1-5 × 5 / 3]
=2 / 3 * 3
=2

There are always two symmetries on the parabola y 2 = 4x with respect to the straight line y = k x + 3

Let B and C be symmetric with respect to the straight line y = KX + 3, so let the BC equation of the straight line be x = - KY + m, and substitute y2 = 4x to get Y2 + 4ky-4m = 0. Let B (x1, Y1), C (X2, Y2), then the midpoint m (x0, Y0) of BC, then Y0 = Y1 + Y22 = - 2K, x0 = 2k2 + M. ∵ point m (x0, Y0) is on the straight line L, ∵ - 2K = K (2k2 + m) +

Solving the combination problem of encounter problem and pursuit problem
For example, a marching column moves at the speed of 7 kilometers per hour, and the correspondent at the end of the column rushes to the front of the column at the speed of 11 kilometers per hour to send a letter, and then returns to the end of the column immediately. It takes 13.2 minutes to find the length of the end of the column

All the officers and men of a certain regiment of the people's Liberation Army march in two columns. They advance at the speed of 8 kilometers per hour. During the procession, the correspondent receives an order from the political commissar at the end of the regiment, asking him to hand over a document to the leader in front of the regiment immediately, and then return to the end of the regiment. The correspondent rushes to the front of the regiment at the speed of 12 kilometers per hour

Given that the distance between two fixed points a and B on the plane is 2a, the ratio of the distance between point m and two points a and B is 2:1, the trajectory equation of moving point m is obtained

Connect AB, set the midpoint of AB as the origin o, take the straight line where AB is as the x-axis, and the vertical line of AB as the y-axis to establish the plane rectangular coordinate system, then it is easy to get the point a coordinate as (- A, 0), the point B coordinate as (a, 0), and the point m coordinate as (x, y)

The problem of factorization of quadratic trinomial with quadratic coefficient of one

(the sign is square)
x"-6x-7=(x-7)(x+1)
It is decomposed into the form of (x + a) (x + b), where a and B satisfy that the product of two numbers is equal to the constant term, and the sum of two numbers is equal to the coefficient of the first term. This is cross multiplication

How many days is it from December 16, 2011 to May 26, 2012

163 days

Help me with the formula
A piece of ore weighs 10N and is hung on a spring dynamometer. When the ore is immersed in water, the real number of the spring dynamometer is 7.5n, then: (1) the volume of the ore; (2) the density of the ore. The formula is needed

According to the title, the ore is buoyant by 2.5n
The volume of ore is equal to the volume of water discharged
F = P water GV
V=2.5/1000*10=2.5*10^-4(m³)
The mass of ore is m = g / g = 1 (kg)
The density of ore is p ore = m / v = 4000 (kg / M & # 179;)

New year's Day is Monday, so the national day of the same year is Monday______ ．

From the new year's day to the national day, there are nine months, including 1, 2, 3, 4, 5, 6, 7, 8 and 9 months. Among them, 1, 3, 5, 7 and 8 are big months, with 31 × 5 = 155 days; 4, 6 and 9 are small months, with 30 × 3 = 90 days. If it is a normal year, there are 28 days in February. 152 + 90 + 28 = 270 (days); 273 △ 7 = 39; so new year's Day is Monday

The formula of multiplicative distribution law

In letters:
（a+b）x c=axc+bxc
There is another expression:
a(b+c)=ab+ac
You can also use:
(a+b)•c=a•c+b•c