After listening to this story, I burst into laughter Be sure

After listening to this story, I burst into laughter Be sure

Hearing this story, I couldn't help laughing
Listen to this story, I (we) coincidentally laugh
Listening to the story, I couldn't help laughing

After listening to the story, we all laughed
I don't think so. Strange

It's just a bone in the egg sentence
This is the only way to change it
We listened to the story and laughed at it

∫ is the derivative of F (x) DX f (x) DX or F (x) DX?

It's f (x)

What are the methods and principles for determining protein content

Determination of protein concentration by Bradford method
（1） Experimental principle
The obvious shortcomings and limitations of biuret and Folin phenol reagent methods urge scientists to search for better eggs
Methods for the determination of white matter solution
Bradford method, which was established by Bradford in 1976, is based on the principle of combining protein with dye
This method is the most sensitive method for protein determination
Law
Coomassie brilliant blue G-250 can bind to protein in acidic solution, which makes the maximum absorption peak of Coomassie brilliant blue G-250 change from 465nm to 595n
m. The color of the solution also changed from brown black to blue
The absorbance value a 595 nm is proportional to the protein concentration
The outstanding advantages of Bradford method are as follows
(1) It is estimated that the sensitivity of this method is about four times higher than that of Lowry method, and the minimum protein detection amount can reach 1 & ᦇ 61549; G
The protein dye complex has higher extinction coefficient, so the change of light absorption value with protein concentration is larger than that of Lowry method
Many
(2) The method is rapid, simple and needs only one reagent. It only takes about 5 minutes to complete the determination of a sample
It takes only about 2 minutes to finish, and its color can be stable within 1 hour, and the color stability is the best between 5 minutes and 20 minutes
Therefore, there is no need to waste time and control time strictly like Lowry method
(3) For example, K +, Na +, Mg2 +, Tris buffer, sugar and sucrose, glycerin, mercaptoethanol, EDTA and so on were not affected by Lowry method
Interference with this method

Find the differential of y = [(e ^ x + e ^ (- x)] ^ 2,

y'=2(e^x+e^(-x))(e^x-e^(-x)) =2(e^2x+e^(-2x))

Finding the n-th derivative of function y = 1-x / 1 + X

y = (1-x)/(1+x)= [2-(1+x)]/(1+x) = 2/(1+x) - 1
dy/dx = -2/(1+x)²
d²y/dx² = -2²/(1+x)³
d³y/dx³ = 3×2²/(1+x)⁴
.
dⁿy/dxⁿ = (-1)ⁿ×2×n!/(1+x)ⁿ+¹

In 1992 / 1993, the numerator subtracts a number, the denominator adds the number, and the fractional value is 2 / 3. Find the number

Let X be the number
(1992-x)/(1993+x)=2/3
Namely
3(1992-x)=2(1993+x)
Solution
x=358

It is known that y = 1, y = x, y = x ^ 2 are three solutions of a second order nonhomogeneous linear differential equation
The question is "then the general solution of the equation is?"
I've read the answers in the book, and they all say
"And y = 1, y = x, y = x ^ 2 are linearly independent, so the difference between any two + the third is the general solution“
”Then the difference between any two solutions is taken as the general solution of the corresponding homogeneous equation. For example, C1 (1-x ^ 2) + C2 (x-x ^ 2) + x ^ 2 or C1 (x ^ 2-x) + C2 (x ^ 2-1) + X can write many similar results“
”C1 (x - 1) + C2 (xsquare - 1) are the general solutions of homogeneous differential equations“
What I want to ask is
Theorem 2 on page 326 of Tongji sixth edition of higher mathematics is as follows
”If Y1 (x) and Y2 (x) are two special linearly independent solutions of the equation y "+ P (x) y '+ Q (x) y = 0, then
Y = c1y1 (x) + c2y2 (x) (C1, C2 are arbitrary constants)
It is the general solution of the equation y "+ P (x) y '+ Q (x) y = 0
In this case, can I have the following answers to this question?
y=C1+C2x+x^2

No, where y "+ P (x) y '+ Q (x) y = 0 is a homogeneous equation
But the title said is the non-homogeneous equation

Decomposition factor M & # 178; n (m-n) & # 178; - 2Mn (n-m) & # 179;

The original formula = M & # 178; n (m-n) & # 178; + 2Mn (m-n) & # 179;
=mn(m-n)²[m-2(m-n)]
=mn(m-n)(2n-m)

What kind of bracket should be added to (23 56) - 22 * 55 in Excel to calculate subtraction first and then multiplication

Use parentheses:
=((23 56)-22)*55
What does your "(23 56)" mean?