MATLAB: MATLAB Error using .*. Matrix dimensions must agree

3d plotsMATLAB

Hello!

Could you help me with the next?

I'm trying to plot a 3d graph writing this:

u = linspace(0,pi,60);  
v = linspace(0,pi,60);  
x = cos(v).*sqrt(abs(sin(2.*u))).*cos(u);  
y = cos(v).*sqrt(abs(sin(2.*u))).*sin(u);  
[X,Y] = meshgrid(x,y);  
Z = X.^2 - Y.^2 + 2.*X.*Y.*(tan(v)).^2;  
surf(X,Y,Z);

But I'm getting an error that tells:

Error in m07 (line 6):
Z = X.^2 - Y.^2 + 2.*X.*Y.*(tan(v)).^2;

What's wrong?

Thanks for your help.

Best Answer

Well X and Y are 60x60 matrices whereas V and thus tan(V).^2 are 1x60 vectors. You can't multiply the two together elementwise since they don't have the same number of elements.

You must have meant something else than tan(V) in the second part of your expression.

Related Solutions

MATLAB: Can someone help me with these 3D plots

you can plot these shapes in the following two ways(you can choose better way you like):

%%Seashell

[u, v] = meshgrid(linspace(0, 6 * pi, 100), linspace(0, 2 * pi, 100));
x = 2 * (1 - exp(u / (6 * pi))) .* cos(u) .* (cos(0.5 * v))^2;
y = 2 * (-1 + exp(u / (6 * pi))) .* sin(u) .* (cos(0.5 * v))^2;
z = 1 - exp(u / (3 * pi)) - sin(v) + exp(u / (6 * pi)) .* sin(v);
figure, surf(x, y, z), xlabel('x'), ylabel('y'), zlabel('z'), title('Seashell')
%%Eight torus

c = 1;
[u, v] = meshgrid(linspace(-pi, pi, 100));
x = cos(u) .* (c + sin(v) .* cos(u) - sin(2 * v) .* (sin(u) / 2));
y = sin(u) .* (c + sin(v) .* cos(u) - sin(2 * v) .* (sin(u) / 2));
z = sin(u) .* sin(v) + cos(u) .* (sin(2 * v) / 2);
figure, surf(x, y, z), xlabel('x'), ylabel('y'), zlabel('z'), title('Eight torus')
%%Helical spring

r1 = 0.25;
r2 = 0.25;
T = 2;
n = 6;
[u, v] = meshgrid(linspace(0, 2 * n * pi, 100), linspace(0, 2 * pi, 100));
x = (1 - r1 * cos(v)) .* cos(u);
y = (1 - r1 * cos(v)) .* sin(u);
z = r2 * (sin(v) + T * u / pi);
figure, surf(x, y, z), xlabel('x'), ylabel('y'), zlabel('z'), title('Helical spring')
%%Cornucopia

a = 0.3;
b = 0.5;
[u, v] = meshgrid(linspace(0, 2 * pi, 100), linspace(-3, 3, 100));
x = exp(b * v) .* cos(v) + exp(a * v) .* cos(u) .* cos(v);
y = exp(b * v) .* sin(v) + exp(a * v) .* cos(u) .* sin(v);
z = exp(a * v) .* sin(u);
figure, surf(x, y, z), xlabel('x'), ylabel('y'), zlabel('z'), title('Cornucopia')

Or alternatively you can also plot them using ezsurf as follows:

syms u v
%%Seashell
x = 2 * (1 - exp(u / (6 * pi))) * cos(u) * (cos(0.5 * v))^2;
y = 2 * (-1 + exp(u / (6 * pi))) * sin(u) * (cos(0.5 * v))^2;
z = 1 - exp(u / (3 * pi)) - sin(v) + exp(u / (6 * pi)) * sin(v);
figure, ezsurf(x, y, z)
%%Eight torus
c = 1;
x = cos(u) * (c + sin(v) * cos(u) - sin(2 * v) * (sin(u) / 2));
y = sin(u) * (c + sin(v) * cos(u) - sin(2 * v) * (sin(u) / 2));
z = sin(u) * sin(v) + cos(u) * (sin(2 * v) / 2);
figure, ezsurf(x, y, z)
%%Helical spring
r1 = 0.25;
r2 = 0.25;
T = 2;
n = 6;
x = (1 - r1 * cos(v)) .* cos(u);
y = (1 - r1 * cos(v)) .* sin(u);
z = r2 * (sin(v) + T * u / pi);
figure, ezsurf(x, y, z)
%%Cornucopia
a = 0.3;
b =0.5;
x = exp(b * v) .* cos(v) + exp(a * v) .* cos(u) .* cos(v);
y = exp(b * v) .* sin(v) + exp(a * v) .* cos(u) .* sin(v);
z = exp(a * v) .* sin(u);
figure, ezsurf(x, y, z)

I hope it helps. Good luck!

MATLAB: How to shift a fsurf plot

r = @(u,v) 2 + sin(7.*u + 5.*v);
funx = @(u,v) r(u,v).*cos(u).*sin(v);
funy = @(u,v) r(u,v).*sin(u).*sin(v);
funz = @(u,v) r(u,v).*cos(v);
% fsurf(funx,funy,funz,[0 2*pi 0 pi]); % This plot should be shifted
xshift = 2; yshift = -2;
% fsurf( @(u,v)funx(u-xshift,v-yshift), @(u,v)funy(u-xshift,v-yshift), @(u,v)funz(u-xshift,v-yshift), [0 2*pi 0 pi])
M = 100 ; N =100 ;
u = linspace(0,2*pi,M) ;
v = linspace(0,pi,N) ;
[U,V] = meshgrid(u,v) ;
X = funx(U,V)-2 ;
Y = funy(U,V)+2 ;
Z = funz(U,V) ;
surf(X,Y,Z)

Best Answer

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MATLAB: Can someone help me with these 3D plots

MATLAB: How to shift a fsurf plot

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