What does KEY 1, A, 3, bB, 2 B 1 and so on in the piano mean?

key is the key,,1=A is a major, The rest is the value of how many times the rest is represented, There is no meaning in rushing up and down the stave,,With C key so as the center,,, you think about it, is the spectrum written in one direction good,,That's why it's up and down in the position of so。 The hollow represents the 4th note and the solid represents the 8th note. Even together is called legato,,The wavy line is an arpeggio。。

I suggest you buy this music theory and say that it is difficult to explain ,,, symbols in words, and music theory says that there is a ** and the solution is also very easy to understand.

In MATLAB, A(:,1:2:3) represents the values of columns 1 and 3 of matrix A.

Note: Before the comma in a: indicates all rows, and the 1:2:3 after the comma indicates that the column takes the value from 1 to 3, and the step size is 2, so the value that can be taken in the column is 1 and 3.

MATLAB, along with Mathematica and MAPLE, is known as the three major mathematical software. It is second to none in numerical calculations among mathematical technology applications.

MATLAB can perform matrix operations, draw functions and data, implement algorithms, create user interfaces, connect programs to other programming languages, etc., and is mainly used in engineering computing, control design, signal processing and communication, image processing, signal detection, financial modeling, design and analysis, and other fields.

a.

First dimension":", as an ellipsis, that is, the line takes all.

The second dimension"1:2:3", is from 1 to 3 steps to 2, that is, the column takes 1 and 3 columns.

In MATLAB, a(1:2)=[ ] means that the first and second elements of array a are emptied.

For example, if the array a=[1,2,3,4,5,6], the result of the execution statement is a=[3,4,5,6].

MATLAB is a high-level matrix array language that includes control statements, functions, data structures, inputs and outputs, and object-oriented programming features. Users can synchronize input statements with executed commands in the command window, or they can write a large and complex application (M file) before running it together.

The new version of the MATLAB language is based on the most popular C++ language, so the syntax features are very similar to the C++ language, and it is simpler and more in line with the format of mathematical expressions written by scientists. Make it more convenient for non-computer professionals to use.

Moreover, this language is portable and extensible, which is also an important reason why MATLAB can penetrate into various fields of scientific research and engineering computing.

A comma in parentheses in a matrix is used to separate different dimensions.

For example, a is a one-dimensional vector, and a(1) represents the first element.

If a is a two-dimensional matrix, then a(m,n) needs to represent the mth row and the nth column matrix, if there is a colon, such as a(:,n) means that the number of columns is n and the number of rows is arbitrary ownership, that is, the nth column of the matrix is removed, and the corresponding a(m,:) represents all the elements of the mth row of a.

Let's look at a (end:-1:1,:, the same comma before the row and the column after it, and the part of the column is a colon, which means that the number of columns is arbitrary, that is, the operation of the whole row of a; Before the comma, end represents the last line, 1 represents the first row, and -1 indicates the entire column of a from back to front, which is generally used in order, such as a(2:1:end,:

It means to take the last line from the second line of A, 1 represents the interval when taking the line, if A(2:2:end,:, it means that every two lines take a line, that is, the line goes down to end. The situation of the column is similar, so let's not talk about it.

..is an abbreviated form of another matrix, b(2:end-1,3:end)+An operation that represents two matrices.

Rows J-2 to J3 of B, and columns I-1 to I2 are all assigned values of 1

That is, b takes the row of a, and all columns, that is, b is the matrix of a flipping up and down, which is equivalent to b=flipud(a).

Matrices: Solving systems of linear equations is a core part of the Linear Algebra course, and matrices play a pivotal role in solving systems of linear equations. The scientific computing software MATLAB is used to demonstrate the use of matrices, and at the same time, it also makes students' understanding of linear algebra more rational.

Matrix construction: In MATLAB, there are two ways to construct matrices. One is the direct method, which is to directly construct the matrix through keyboard input. The other is to use functions to generate matrices.

a=[1,2,3;4,5,6;7,8,9] represents the input matrix a, and the first row is 1,2,3; The second row is 4, 5, 6; The third line is 7, 8, 9.

b=a(3:-1:1,1:3) means that b is equal to the row of the a matrix, and all the columns, that is, b is a matrix that flips up and down, which is equivalent to b=flipud(a).

Braces are cell structures.

The parentheses are matrix structures.

A is a cell structure, and you can think of it as a new matrix made up of many submatrices. Each position is a matrix, and a position under each matrix is a numeric value.

The meaning of this formula is to find the number in column A of the standard table of AA that is less than 1 than the number of cells in the J3 cell of the current table, and then take the number of column B in the AA table.

Layman's Explanation:

in the table"AA standard"In the A3 to A68 area, find the row that exactly matches the content of the name J3-1, and display the content of the cells in column b of this row.

For example, a=(a1,a2,a3),b=(b1,b2,b3) then axb is bai[ i, j, k;

a1,a2,a3;

b1,b2,b3]

The value of the du determinant of this matrix should be daoa b=(a2b3-a3b2)*i+(a3b1-a1b3)*j+(a1b2-a2b1)*kThe result is a vector. Assets.

The material is dot product, right.

The multiplication of the weighted elements is denoted as a·b=a1b1+a2b2+a3b3, which is wrong in the data, because the dot product obtains a number, that is, a scalar quantity, without direction.

axb=[i,j,k;

a1,a2,a3;

b1,b2,b3];

The latter is a matrix, which is represented in MATLAB.

The data says that a1b1*i+a2b2*j+a3b3*k, and this result is the dot product result, not the cross product result.

Left meaning.

left(sheet1!b1,6)

Extract the 6 digits to the left of B1, then look for this number, in A:B, if column A has the same number as this number, the data corresponding to column 2 (column B) will be displayed.