A Theoretical Analysis Method of Spatial Analytic Geometry and Mathematics under Digital Twins

Table 3

Matlab program of geometry.

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r = 0 : 0.2:sqrt(2);

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t = 0 : 0.2 : 2  pi + 0.2;

[T, R] = mesh grid(t, r);

X = cos(T).  R;

Y = sin(T).  R;

Z = X.^2 + 2  Y.^2

axis([−3, 3, −3, 3, −15]);

hold on;

quiver3(0, 0, 0, −1.5, 0, 0, 2.2, “k,” “filled” “LineWidth,”1.6)

quiver3(0, 0, 0, 0, −1.5, 0, 2.2, “k,” “filled” “LineWidth”, 1.6)

quiver3(0, 0, 0, 0, 0, 0, 2.5, 3, “k,” “filled” “LineWidth,” 1.6)

text(0, −0.6, 8, “Z”);

text(0, −4, 0, “Y”);

text(−4, 0, 0.2, “X”);

axis off;

hold on;

set(gef, “color,”[1 1 1]);

surf(X, Y, Z, “FaceColor,” “g”);

z = 6-2  X.^2- Y.^2

surf(X, Y, Z, “EdgeColor,””None”);

hold on;

X = squrt(2)  cos(t)

Y = squrt(2)  sin(t)

Z = X.^2 + 2  Y.^2;

plot3(X, Y, Z, “k”,”LineWidth,” 3);

hold on;

view(0, 90)

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