Or use mesh for one surface and surf for the other, so here's my favorite version of the plot: mesh(3*cos(s).*sin(t),2*sin(s).*sin(t),cos(t)), axis equal, hold on For example, to plot the ellipsoid above and the cylinder parametrized by you can use the following commands: =meshgrid(0.02*pi:2*pi,0.02*pi:pi) Īnd then surf(3*cos(s).*sin(t),2*sin(s).*sin(t),cos(t)), axis equal, hold on To plot more than one surface you have to use the mesh or surf commands - you can't use ezsurf or ezmesh for the first surface because it will undo the effect of a hold on command. Notice that since I am using a grid, I am effectively working with matrices I need to multiply two of them component by component (not using ordinary matrix multiplication), so I need a period after the first one. You can then plot it with surf or mesh surf(3*cos(s).*sin(t),2*sin(s).*sin(t),cos(t)) You start by creating a grid of points (the parameter values which will be used for plotting). Which gets you a solid shaded surface or with syms s tĮzmesh(3*cos(s)*sin(t),2*sin(s)*sin(t),cos(t))Īnother way to plot this surface is to use surf or mesh, which gives you more control over the plot. You can do this with the commands syms s tĮzsurf(3*cos(s)*sin(t),2*sin(s)*sin(t),cos(t)) (This is just spherical coordinates, calling the angles s and t, which are shorter to type than theta and phi.) One way to plot this is to use ezsurf or ezmesh. For example, for the ellipsoid I can use with To parametrize the surface given by the equation f(x,y,z)=0, you need functions x(s,t), y(s,t) and z(s,t) so that f(x(s,t),y(s,t),z(s,t))=0. Since it is two dimensional, there will be two parameters. To plot a surface, you may want to think of the surface as parametrized. Give the command before giving the command for the plot you want to appear in the new window. If MATLAB ignores hold off (which it does occasionally), give the command clf The first thing is to try is the command hold off before the new plot command. Preventing MATLAB from putting a new plot on top of an old one Here is the new blank (and invisible) figure. You can get a new figure window by giving the command figure syms xĪlternatively, you can create an anonymous constant function and plot that. So, for example, to use it to plot the constant function 5, you can write 5 as 5+0*x and plot that. Solve('x^2-5*x=6') Plotting a constant function with ezplotĮzplot requires a variable in a symbolic expression.
Or you can give the solve command an equation enclosed in single quotes: The command solve(x^2-5*x=-6) gives the error messageĮrror: The expression to the left of the equals sign is not a valid targetĪnd solve(x^2-5*x+6=0) gives a similar error message. Suppose you want to solve the equation x^2-5*x=6.
The solve command takes as its input a symbolic expression, not an equation and assumes that the expression is equal to 0. If MATLAB doesn't recognize the quadl command, make sure that you have typed it correctly. MATLAB (and most mathematical software) knows the natural logarithm as log(x). MATLAB (and most mathematical software) knows the exponential function as exp(x) so the number e in MATLAB is exp(1). The exponential function and the number e If you have a space or hyphen, when you publish to html MATLAB will give an error message when it tries to execute the first command and won't try to execute any later commands. Fixing a bad pagebreak in your html fileĭo not have a space or a hyphen in the names of your.A command for rotating a 3 dimensional plot.
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