Trying To Plot a 3D shape

I want to create the above 3D shape using the given integral bounds. I want to use the bounds to create the shape in matlab.

I've already written a few lines and created the figure below. I don't know why it's showing me just a line.

What other peice of information am I missing?

Thank you.

clear, clc 

x = [0:.01:1];

xx = meshgrid(x);

zz = 1 - xx.^2;

yy = 1 - xx;

surf(xx,yy,zz)

Answer 1

[Star Strider]

You need a second output from meshgrid in order to plot ‘yy’ correctly.

Try this:

x = 0:0.01:1;
[xx1,xx2] = meshgrid(x);
zz = 1 - xx1.^2;
yy = 1 - xx2;
zzc = zz.*(xx1 <= xx2);
mesh(xx1, yy, zzc)
xlabel('X')
ylabel('Y')
view(125, 30)

producing:

Experiment to get the result you want.

[Lucas Clark]

Thank you for the help!!

I'll tinker with it some more, I need a better understanding of mesh grid.

What is the reasoning behind this line of code? (5th line down):

zzc = zz.*(xx1 <= xx2)

Thank you again.

[Star Strider]

As always, my pleasure!

The ‘zzc’ assignment is a way of forcing the linear relation of ‘yy’.

An alternative is:

x = 0:0.01:1;
[xx1,xx2] = ndgrid(x);
zz = 1 - xx1.^2;
yy = 1 - xx1;
zzc = zz.*(yy >= xx2);
mesh(xx2, yy, zzc)
xlabel('Y')
ylabel('X')
view(25, 30)

with the axis labels reversed because ndgrid produces different results than meshgrid.

This actually makes more sense. (It took a while to get as far as I did, since your assignment and the meshgrid output are not compatible. The ndgrid result and the calculations using it are more logical.) The plot is essentially the same, so I am not re-posting it here.