MATLAB. .
, , . . . . , . . char. . . . .
, ,
. 2.1. MATLAB
. 2.2.
. 2.3. .
MATLAB , MATLAB, . MATLAB :
- ;
- Help;
- MATLAB.
MATLAB , .
>> help
(), m- , (. 2.4). , MATLAB .
. 2.4
>> help elfun
(. 2.5).
. 2.5
help < >, ,
>> help asinh
>> help /
doc elfun, Help MATLAB, . . , , doc < >, , (. 2.6)
>> doc asinh
. 2.6
Help Toolboxes (. 2.7). Getting Started (), , Examples () (. 2.8).
MATLAB, . Open this Example ( ) . , , .
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, , Evaluate Selection (. 2.9).
, , .
: doc ops ; doc function -.
. 2.7
. 2.8
. 2.9
. , -- y''-μ(1-y2)y'+y=0, "Van der Pol" ( , , "Ordinary Differential Equations" "MATLAB > Mathematics > Numerical Integration and Differential Equations", )
. . , .
MATLAB, . , MATLAB, . () . , MATLAB, .
0
1
-93
7.5674
0.00000047
.
3.3333e-4
-75.8e13
e, .. 3.3333e-04 3.3333×10-4 0.00033333.
. , 10e8 1.0e9, 1 000 000 000, . e , :
>> 10 e8
??? 10 e8
Error: Missing operator, comma, or semicolon.
, . :.5 0.5.
, MATLAB . double ( ). , MATLAB , .
( ) 8 . 15 . 2.2250738507201e-308 1.797693134862316e+308. realmin realmax.
MATLAB double. , () . MATLAB single, ( 4 ). .
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: int8, uint8, int16, uint16, int32, uint32, int64, uint64, 8, 16, 32 64 . u 0 .
int8 8 . -128 +127 (. -27 27 - 1).
uint8 int8, 0 255 (28 - 1).
, , double, , .
,
>> x=int32(3.2)
int32.
doc double, doc single, doc int8, doc uint8.
:
>>e=int8(2.2)
e=
>>e=int8(2.8)
e=
MATLAB :
>>e=[2]
e=
. , MATLAB short (), . . Command Window. Preferences (). Preferences, . 2.10.
. 2.10
, Command Window ( . 2.10). Numeric format Text display. short Numeric format. , . , . 200/3 <Enter>. short:
>> 200/3
ans =
66.6667
, . MATLAB , short. 100000/3 1/3000 :
>> 100000/3
ans =
3.3333e+004
>> 1/3000
ans =
3.3333e-004
, short . , Preferences long. long . short e long e . , doc format.
format. :
>> format long e
>> 1.33/5.13
ans =
2.592592592592593e-001
>> format long g
>> ans
ans =
0.259259259259259
>> format rat
>> 0.03333333
ans =
1/30
, format rat , .
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, , MATLAB . . Preferences compact Numeric display. . loose Numeric display.
format format short format loose.
MATLAB , , .
, - . , , . . , , .. , (, ).
( ) 63 (MATLAB 2014a, . namelengthmax) , , MATLAB. , . MATLAB , _. , (. genvarname). ,
arg = 1;
Arg = 2;
ARG = 3;
, .. 1, 2 3 . MATLAB .
, . .
MATLAB , . . . , .. .
MATLAB.
- ans .
- i, j (), .
- Inf (infinity) .
- NaN Not-a-Number ( ), (, 0/0 Inf/Inf).
- pi π (p=3,141592653589793).
- eps , . 1.0 2.2204e-16.
- realmin (2.2251e-308).
- realmax (1.7977e+308).
. char . . , .
>> name=char('123')
name =
MATLAB :
3+2i; 7-4j; -3.8952+1.23e-5i; 5+i*7.
real imag :
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>> real(z)
ans =
-9
>> imag(z)
ans =
complex :
>> z=complex(3,-4)
z =
3.0000 - 4.0000i
conj :
>> conj(z)
ans =
3.0000 + 4.0000i
, :
>> z=1+2*i'
z =
1.0000 - 2.0000i
>> z'
ans =
1.0000 + 2.0000i
abs(x) -
angle(x) - ( ) , , .. arctg
isreal(x) - , 1 () , ( ) (0)
, .. ( Enter) , . .
>> 5*exp(-j*pi/6)
ans =
4.3474 - 2.4699i
MATLAB. a b. , , :
c = a+b; %
c = a-b; %
c = a*b; %
c = a/b; %
, MATLAB , :
c = a^2; % a
c = a^0.5; % a
* / + -, .. , , . . , , ,
c = 7+2*2; % c = 28
c = (7+2)*2; % = 18
. . /, \. :
>> 8\2
ans =
0.2500
>> 8/2
ans =
.. , , .. , .
MATLAB:
& -
| -
~ -
a < b | , a b . |
a > b | , a b . |
a == b | , a b . |
a <= b | , a b . |
a >= b | , a b . |
a ~= b | , a b . |