Matlab learning ------ values, variables and expressions, matlab ------

Matlab learning ------ values, variables and expressions, matlab ------

(1) plural

Multiple numbers can be input directly according to the expression (do not use variables whenever possible), or between numbers and virtual parts *

Example:

>> num=3+4inum =   3.0000 + 4.0000i>> num=3+4*inum =   3.0000 + 4.0000i

Complex operation functions:
Real (z) calculates the real part of the plural;

Imag (z) is used to obtain the imaginary part of the plural number;

Abs (z) calculates the modulus of the plural;

Angle (z) calculates the phase angle of the plural.

Instance:

>> num=3+4*inum =   3.0000 + 4.0000i>> real(num)ans =     3>> imag(num)ans =     4>> abs(num)ans =     5>> angle(num)ans =    0.9273

(2) Inf and NaN

Inf is the abbreviation of Infinity, indicating positive Infinity. This constant must be introduced when 0 is used for Division;

NaN is the abbreviation of Not-a-Number, indicating a non-numeric value.

Instance:

>> 1/0ans =   Inf>> 0/0ans =   NaN

(3) Determine whether the input is a Matlab Keyword: iskeyword

>> iskeywordans =     'break'    'case'    'catch'    'classdef'    'continue'    'else'    'elseif'    'end'    'for'    'function'    'global'    'if'    'otherwise'    'parfor'    'persistent'    'return'    'spmd'    'switch'    'try'    'while'>> iskeyword whileans =     1>> iskeyword('while')ans =     1

How does matlab assign values to variables in a symbolic expression?

What are D, P, and Q?

How can I assign values to multiple variables in a matlab expression?

Multiple Substitutions:
Subs (cos (a) + sin (B), {a, B}, {sym ('alpha'), 2}) returns
Cos (alpha) + sin (2)

Use subs.

Then, use the double command to convert it to a value.