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:
= [16 3 2 13; 5 10 11 8; 967 12; 4 15 14 1]
MATLAB , ,
A =
16 3 2 13
5 10 11 8
9 6 7 12
4 15 14 1
, MATLAB. . , MATLAB, , . ?
, , . - , - , . , MATLAB. , -
sum ()
MATLAB
ans =
34 34 34 34
, MATLAB ans, answer - , . -, . , , , 34. ? , , . . .
sum(A') '
-,
ans = 34
|
|
diag, .
Diag (A)
ans = 16
sum (diag ())
ans = 34
, , ,
MATLAB . ,
, fliplr,
.
Sum(diag(fliplr(A)))
ans = 34
i j A(i,j). ,
(4,2) - .
(4,2) = 15. ,
,
A(1,4) + (2,4) + (3,4) + (4,4)
ans = 34
.
, A(k). . . , .
, , (8) - 15, (4,2).
, MATLAB :
t=A(4,5)
??? Index exceeds matrix dimensions.
, ,
.
X=A;
X(4,5) = 17
X =
16 3 2 13 0
5 10 11 8 0
9 6 7 12 0
4 15 14 1 17
: - MATLAB.
.
1:10
- -, 1 10
123456789 10
, .
100:-7:50
100 93 86 79 72 65 58 51
0:pi/4:pi
0.7854 1.5708 2.3562 3.1416
, , .
A(1:k, j)
k j - .
sum(A(l:4,4))
. . ,
, , end
.
sum ( (:, end))
ans = 34
, MATLAB
,
, MATLAB .
:
MATLAB . MATLAB , . , MATLAB . ,
num_students = 25
1x1 num_students 25
.
, . MATLAB
31 . MATLAB
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2.1
MATLAB ,
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i j .
3 -99 0.0001
9.6397238 1.60210e-20 6.02252e23
1i -3.14159j 3e5i
- 16
10-308
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2.3
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2.4
MATLAB , abs, sqrt, exp, sin. : . MATLAB
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help elfun ,
help specfun
help elmat
.
, sqrt sin, - .
MATLAB, ,
. , gamma
sink, -.
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.
pi 3.14159265...
i , √-1
j , i
realmin , 2-1022
realmax , (2-ε)21023
Inf
NaN
, , .. realmax.
(NaN) / Inf-
Inf, .
,
,
eps = 1.e-6
.
clear eps
MATLAB
, .
.
3.1
plot , ,
plot(y) -
. ,
plot(x,y) .
|
|
, sin
2π,
t = 0:pi/100:2*pi;
= sin(t);
plot(t,)
plot -
. MATLAB (
, ),
. , ,
:
2 = sin(t-.25);
= sin(t-.5);
plot(t, , t, y2, t, )
, ,
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plot(x, , '__')
__ 1-, 2-, 3- (
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plot(x,y,'y:+')
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, MATLAB .
plot (
), . , plot
. ,
figure
, -
figure(n)
n - .
.
hold .
hold on
MATLAB , ,
, . ,
peaks,
:
[x,y,z] = peaks;
contour(χ,,z,20,'k')
hold on
pcolor(x,y,z) shading interp
hold on , pcolor
contour
3.2
subplot
.
subplot(m,n,p)
m n n-
. ,
.. , ,
:
t = 0:pi/10:2*pi;
[Χ,Υ,Ζ] = cylinder(4*cos(t));
subplot(2,2,1)
mesh(X)
subplot(2,2,2); mesh(Y)
subplot(2,2,3);mesh(Z)
subplot(2,2,4); mesh(X,Y,Z)
3.3
axis ,
.
MATLAB
. axis
, .
axis([xmin xmax ymin ymax])
axis
|
|
.
axis square
χ ,
axis equal
χ .
plot(exp(i*t))
axis square, axis equal
.
axis auto
.
axis on
.
axis off
.
grid off
,
grid on
.
3.4
xlabel, ylabel, zlabel ,
title , text
.
, .
.
t = -pi:pi/100:pi;
= sin(t);
plot(t,)
axis([-pi pi -1 1])
xlabel(' -\pi \leq \itt \leq \pi ')
ylabel(' sin(t) ')
title(' sin ')
text(-l, -1/3, ' \it{ } ')
3.5 mesh surface
MATLAB ζ
-, .
mesh surface
.
mesh ,
, surface
.
3.6
, z = f (x,y), X Y,
,
.
. meshgrid ,
x , X Υ
. X
, Υ - .
sinc, sin(r)/r, -
[Χ, Υ] = meshgrid(-8:.5:8);
R = sqrt(X.^2+Y.^2)+eps;
Ζ = sin(R)./R; mesh (Χ, Υ, Ζ)
R - ,
. eps /
.
,
.
load durer whos
, durer.mat demo 648
509 ( X) 128 3 ( ).
X - 1 128,
, .
imag(X)
colormap(map)
axis image
. ,
, .
load detail
''
image, colormap axis.
colormap(hot)
.
3.6
Print File print
MATLAB. Print ,
-. , ,
.
, PostScript.
,
PostScript Level 2 Encapsulated magicsquare.eps:
print -depsc2 magicsquare.eps
print.
, Postscript Level 2
, Postscript Level 1. , Postscript
Level 2, ,
. MATLAB
, - .
, MATLAB,
.
|
|
.
,
, Fixedsys Courier,
.
103
10-3, MATLAB
short long. format,
format compact
, .
.
, sprint/ /print/.
Return Enter, MATLAB
.
, MATLAB , .
. ,
A = magic(100);
, ,
Return Enter, ,
.
s = l -1/2 + 1/3 -1/4 + 1/5 - 1/6 + 1/7... -1/8 + 1/9 - 1/10 + 1/11 - 1/12;
=, +, - , .
, , .
, ,
rho = (1 + sqt(5))/2
sqrt. MATLAB
Undefined function or variable 'sqt'.
, , .
. ←
r.
.
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.
MATLAB
MATLAB ,
MATLAB, , ,
.
5.1
- , MATLAB.
, who whos,
. who , whos
.
, w hos,
, .
MATLAB.
,
.
whos
Name Size Bytes Class
A 4x4 128 double array
D 5x3 120 double array
Μ 10x1 3816 cell array
S 1x3 442 struct array
h 1x11 22 char array
η 1x1 8 double array
s 1x5 10 char array
ν 2x5 20 char array
Grand total is 471 elements using 4566 bytes.
MATLAB,
clear
5.2 save
save -,
load
MATLAB. ,
save Augustl7th
Augustl7th.mat.
, ,
.
MATLAB.
help
MATLAB Help Desk
The MathWorks, Inc.
help
help -
. .
help magic
MAGIC Magic square.
MAGIC(Ν) is an N-by-N matrix constructed from the integers 1 through
ΝΛ2 with equal row, column, and diagonal sums. Produces valid magic
squares for N = 1,3,4,5,...
MATLAB
, . ,
, MATLAB
, .
MATLAB
MATLAB . ,
matfun.
,
help matfun
Matrix functions - numerical linear algebra.
Matrix analysis.
norm - Matrix or vector norm,
normest - Estimate the matrix 2-norm.
lookfor
lookfor .
, H1,
MATLAB H1, .
, MATLAB inverse.
Help inverse
inverse.m not found.
Lookfor inverse
. ,
toolboxes , .
INVHILB Inverse Hubert matrix.
ACOS Inverse cosine.
ACOSH Inverse hyperbolic cosine.
ACOT Inverse cotangent.
ACOTH Inverse hyperbolic cotangent.
ACSC Inverse cosecant.
ACSCH Inverse hyperbolic cosecant.
ASEC Inverse secant.
ASECH Inverse hyperbolic secant.
ASIN Inverse sine.
ASINH Inverse hyperbolic sine.
ATAN Inverse tangent.
-all lookfor, , ,
lookfor -all
,
H1.
, ,
PDF (Portable Document Format) Help Desk.
Adobe's Acrobat reader.
, , ,
.
.