Xiao Ming's father said, "in a moment, I'll buy a story book on the street."

Xiao Ming's father said, "in a moment, I'll buy a story book on the street."

Xiao Ming's father said that after a while, he went to the street to buy a story book

The formulas of attendance rate, rice yield, hit rate, qualified rate, oil yield, germination rate and sugar yield are obtained,

On the equation of exponent and logarithm
Log4 (3-x) + log0.25 (3 + x) = log4 (1-x) + log0.25 (2x + 1)
10 ^ (logx) square of bracket + x ^ (lgx) = 20
Note that the second question is 10 ^ (logx) the square of the whole bracket, not the square of X

Llydmissile is my account number, but the number of modifications has reached the upper limit, so I can't change it any more. So I changed my account number to answer 2

Calculate the area of the plane figure surrounded by the heart line r = a (1 + cosx) (a > 0), and seek the explanation of the big God figure

A difficult problem in the wisdom house
If you add 1 to the numerator of a fraction, the fraction is equal to one. If you add 1 to the denominator of the fraction, the fraction is equal to eight out of nine. What is the original fraction? If you add 2 to the denominator of the fraction, it is equal to eight out of nine, what is the original fraction?

Let the numerator be x and the denominator be y
The first question: x + 1 = y, X / (y + 1) = 8 / 9;
9x=8(y+1)
Substituting: 9x = 8 [(x + 1) + 1]
The solution is x = 16, y = 17, and the original fraction is 16 / 17
Similarly, the second question x = 24, y = 25, the original score is 24 / 25

The monotone and bounded interval of function f (x) = LX & # 178; - 1L is [- 1,1]; (1, positive infinity) '[- 2,0] [- 2, - 1], which one should be chosen

[- 2, - 1] single subtraction

Is there a real number α such that sin α + cos α = √ 3

If there is! The square of both sides is: 1 + 2Sin α cos α = 32sin α cos α = 2, that is, sin2 α = 2 and sin2 α ≤ 12 ≤ 1, so there is no contradiction! If you have not learned the double angle 2Sin α cos α = sin2 α & nbsp;, you can use the following method: sin α cos α = 1sin α cos α / 1 = 1sin α cos α / [sin ^

Who knows the solution of the equation of chicken and rabbit in the same cage?
Title: a cage contains two kinds of animals, chicken and rabbit. They have 70 heads and 200 feet. How many chickens and rabbits are there in the cage?
Must be the solution of the equation. My sixth grade, the total review needs, either can not solve, or my solution is too complex, to be simple
Please don't skip the steps

There are x rabbits
4x＋2(70-x)=200
4x＋140－2x＝200
4x－2x＝200－140
2x＝60
x＝60÷2
x＝30
70-40 = 30
A: there are 40 rabbits and 30 chickens

Help to deduce the derivative formula of function f (x) = SiN x

f(x+a)-f(x)=sin(x+a)-sinx=2cos(x+0.5a)sin0.5a
f(x+a)-f(x)/[(x+a)-x]=cos(x+0.5a)sin0.5a/0.5a
Obviously, there is 0

Given A-B = 1, B-C = 2, a & # 178; + B & # 178; + C & # 178; = 1, then AB + BC + Ca =? Process

A-c = 3 (a-b) is the result of a-C = 3 (a-b-c = 1b-c = 2-b-b-c = 2 to add a-c-b-b-c = 2 to add a-c-b-c = 2 to get a-c = 3 (a-b-b-c-b-c; (b-c-c-c; (c-a-a-a; (c-a-a-c-a; (c-a-a-c-c-a; (c-a-c-a-c-c-c-b-b-b-b-c-2b-2b-2b-2bc-2bc-2bc-2bc-2bc-2bc-2bc-2bc-2bc-2bc-2bc-2bc-2bc-2bc-2bc-2bc-2bc-2bc-2bc-2bc-2bc-2bc-2bc-2bc-2bc-2bc-2bc-2bc-2bc-2bc-(AB + BC + Ca) = - 12ab + BC + Ca = - 6