Find the general solution of the equation (1) XY '- y = y ^ 2 (2) XY' - y ^ 2 + 1 = 0

Find the general solution of the equation (1) XY '- y = y ^ 2 (2) XY' - y ^ 2 + 1 = 0

xy'-y=y^2
(xy'-y)/x^2=y^2/x^2
(y/x)'=(y/x)^2
Two sides integral
-1/(y/x)=x+C
xy'-y^2+1=0
dy/(y^2-1)=dx/x
Two sides integral
1/2ln(y-1)-1/2(y+1)=lnx+C1
That is, (Y-1) / (y + 1) = CX ^ 2

On the tree planting process of tree planting day

1. Prepare tools: hoes, buckets, plants to be planted. If possible, bring some fertilizer
2. Dig a hole to the right depth and width
3. Pad Red Soil (rich soil plus fertilizer), irrigate and mix the soil
4. Put the trees in the pit, backfill the soil and water them properly
You have finished planting trees and can go home
Or plant more trees

Let f (x) = x * x-lxl, if f (- M * m-1)

Because f (x) = x * x-lxl is even function
Increasing on [1 / 2, infinite], and f (0)

There are two kinds of drinks a and B in the supermarket. Xiaoyang bought five bottles of a drinks and four bottles of B drinks for a total of 18 yuan, of which B drinks are 0.3 yuan more expensive than a drinks
The unit price of a drink is x yuan, and that of B drink is y yuan
The solution of quadratic equation of two variables
Please, everyone!

List two equations;
(5 bottles of a drink and 4 bottles of B drink cost 18 yuan in total) 5x + 4Y = 18 style 1
(beverage B is 0.3 yuan more expensive than beverage a) Y-X = 0.3 formula 2
Substituting formula 2 into Formula 1
The solution is as follows
x=1.87
y=2.17

New concept English for young people 2A 2B text (can be copied or sent to the website) and MP3 format file (can be sent to the website) 30 [label: new concept, text, MP3] new concept English for young people 2A lesson 2, 7, 11 new concept English for young people 2B Lesson 18, 27, 28

2A unit 2 good luck on Sunday reporter: my name's Tom French. I'm speaking to you from the Excel Centre in London's Docklands. We are visiting this year's marathon Expo. Reporter: This is the trade f

The speed of cars and trucks is 80 km / h and that of trucks is 65 km / h,
When the car arrived at B, it immediately returned. The distance between AB and AB was 290 kilometers. How many hours later did the two cars meet?

290X2/(80+65)=4

If a = 1 - (- 1) n, n is a positive integer, AB is an opposite number, and BC is reciprocal, try to find the power of a + B + B - (B-C) 2n

When n is odd, a = 2, B = - 2, C = - 0.5, a + B + B ^ n - (B-C) ^ 2n = (- 2) ^ n - (9 / 4) ^ n
When n is even, a = 0, B = 0, C does not exist, so it does not hold

A and B start from a and B at the same time
Car a and car B start from a and B at the same time and travel in opposite directions. Moreover, car a's speed is one fifth faster than car B's. when they meet, car a is still 80 kilometers away from place B. how many kilometers is the distance between a and B?

1 divided by [1 + 1 + 1 / 5] equals 5 / 11, 80 divided by 5 / 11 equals 176

A group of numbers are given in brackets after the following equations, from which the solution of the equation is found: (1) 2x ^ 3-6 = 0, (√ 3, √ 6, - √ 3, - √ 6);
A set of numbers are given in brackets after the following equations to find the solution of the equation:
(1)2x^3 - 6=0,(√3,√6,-√3,-√6);
(2)2(x+5)^2=24,(5+2√3,5-2√3,-5+2√3,-5-2√3).

（1）√3,-√3,
（2）-5+2√3,-5-2√3).

Party A and Party B are on the same road. Party A travels 3 kilometers per hour and Party B 5 kilometers per hour. Party A passes through place a at 12 noon and Party B passes through place a at 2 pm
What time can you catch up with B in the afternoon

Let B catch up with a at x p.m
(x-12)*5=(x-12+2)*3
5x-60=3x-30
2x=30
x=15
B can catch up with a at 15 p.m