When we know the coefficient of present value (or final value) of annuity and the period n, it is a bit unclear to calculate the interest rate according to the interpolation formula Given the coefficient of present value (or final value) of annuity and the number of periods n, it is a little unclear when calculating the interest rate according to the interpolation formula Example: a company borrows 20000 yuan at the beginning of the first year, and repays 4000 yuan at the end of each year, which is paid off for nine consecutive years? （P/A,i,9)=P/A=20000/4000=5 When I = 12%, (P / A, 12%, 9) = 5.3282; I = 14%, (P / A, 14%, 9) = 4.9464 So I = 12% + (5.3282-5) / 5.3282-4.9464) * (14% - 12%) = 13.72% How to define I1 and I2 in the formula? In the above example, choose between 12% and 14%. Why can't we choose between 13% and 14%, choose 13% [i = 13%, (P / A, 12%, 9) = 5.137654]. Isn't it closer to 5 than 12%?

When we know the coefficient of present value (or final value) of annuity and the period n, it is a bit unclear to calculate the interest rate according to the interpolation formula Given the coefficient of present value (or final value) of annuity and the number of periods n, it is a little unclear when calculating the interest rate according to the interpolation formula Example: a company borrows 20000 yuan at the beginning of the first year, and repays 4000 yuan at the end of each year, which is paid off for nine consecutive years? （P/A,i,9)=P/A=20000/4000=5 When I = 12%, (P / A, 12%, 9) = 5.3282; I = 14%, (P / A, 14%, 9) = 4.9464 So I = 12% + (5.3282-5) / 5.3282-4.9464) * (14% - 12%) = 13.72% How to define I1 and I2 in the formula? In the above example, choose between 12% and 14%. Why can't we choose between 13% and 14%, choose 13% [i = 13%, (P / A, 12%, 9) = 5.137654]. Isn't it closer to 5 than 12%?

If you look around P / a = 5, 13% and 14% are preferred. Of course, 13% and 15% are OK. If you choose 12% and 14% in the answer, it just shows that the different choices have little effect on the result

There are two groups of data mean and standard deviation, the correlation coefficient formula?

Can't find out

What does variance expectation covariance correlation coefficient describe or what is its practical significance

Variance describes the fluctuation of a group of numbers. If a series of numbers are all one kind of numbers, such as 1,1,1,1,1, then its variance is 0. Expectation is actually the average value of a group of numbers. Covariance is a statistical analysis method based on variance analysis and regression analysis. The variance between two different parameters is covariance correlation

The concept of correlation coefficient. When the variance is 0, how to calculate the correlation coefficient. When the covariance is 0, is the correlation coefficient 0?
(1) According to the textbook definition, PXY = cov (x, y) / radical (DX * dy). But what happens when DX or dy is 0?
(2) When cov (x, y) = 0, is the correlation coefficient 0?

1. If x and y are random variables, there should be no DX or dy = 0, otherwise they are constants rather than random variables. Therefore, the situation you mentioned does not exist
2. When cov (x, y) = 0, then the correlation coefficient ρ (x, y) is zero

Number set symbol?

Set of non negative integers (or set of natural numbers), denoted as N;
A set of positive integers, denoted as n * or N + ("+" is marked in the lower right corner);
Set of integers, denoted as Z;
The set of rational numbers, denoted as Q;
The set of real numbers, R,
The set of complex numbers composed of all real numbers and imaginary numbers is called complex number set, denoted as C

Seek the meaning and representative symbols of various numbers (number sets) in various high school mathematics
For example: set of natural numbers The set of all non negative integers is called the set of non negative integers, denoted as n

Natural number set: n
Real number set: R
Rational number set: Q
Irrational number set: R-Q
Positive integer set: n * or n+
Integer set: Z
Complex set: C

What does this symbol mean in mathematics
It's this symbol
It is a mathematical problem; if a ⁃ B = 2A + 3b is defined, what is the result of 2 ⁃ 3 ⁃ 2

Didn't the title tell you?
There is no specified meaning for ⁃ B. in the title, "define a ⁃ B = 2A + 3B", that is to say, when there is this symbol between a and B, the result of a ⁃ B is 2A + 3B
There seems to be something wrong with your topic. Let me give you an example!
4 * 5 = 2 * 4 + 3 * 5 = 23, just go in!
Note: * means to multiply, I'm afraid you don't know, come on!

*What does this symbol represent in mathematics

The multiplication sign means to multiply two numbers

What does this symbol mean
[N^2*(N+1)^2 + N^2 + (N+1)^2]/[N^2*(N+1)^2]
The symbol "^" in this formula doesn't understand?
Is it a root sign? "*" this symbol means multiplication?
The symbol "^" in this formula doesn't understand?
Is it a root? Or square? The symbol "*" denotes multiplication?

The symbol "^" denotes index
For example, x ^ 2 = x & # 178;
The symbol "*" can denote multiplication

What does the symbol "^" mean mathematically?

The power of a number
For example, 2 ^ 3 = 2 * 2 * 2 = 8