用matlabTry to plot three dimensional graph of the function z=2*x^2+y^2 , where x=sin3t and y=cos3t . The range of t should be set to [-3, 3], and the ranges of x and y axes are both [-1.2, 1.2]. Requirement: Plot the three-dimensional (3-D) mesh graph, 3-D surface graph and 3-D surface graph with contour lines, respectively. In addition, plot the 2-D sectional view graph for x=1.

Sure, here's the code to plot the three-dimensional graph of the given function in MATLAB:

% Define the function
f = @(x, y) 2*x.^2 + y.^2;

% Define the range of t
t = linspace(-3, 3, 100);

% Calculate the x and y values
x = sin(3*t);
y = cos(3*t);

% Calculate the z values
z = f(x, y);

% Create a meshgrid for the x and y values
[X, Y] = meshgrid(x, y);

% Plot the 3D mesh graph
figure;
mesh(X, Y, z);
xlabel('X');
ylabel('Y');
zlabel('Z');
title('3D Mesh Graph');

% Plot the 3D surface graph
figure;
surf(X, Y, z);
xlabel('X');
ylabel('Y');
zlabel('Z');
title('3D Surface Graph');

% Plot the 3D surface graph with contour lines
figure;
surf(X, Y, z);
xlabel('X');
ylabel('Y');
zlabel('Z');
title('3D Surface Graph with Contour Lines');
hold on;
contour(X, Y, z, 20, 'k');
hold off;

% Plot the 2D sectional view graph for x=1
x1 = 1;
y1 = linspace(-1.2, 1.2, 100);
z1 = f(x1, y1);

figure;
plot(y1, z1);
xlabel('Y');
ylabel('Z');
title('2D Sectional View Graph for x=1');

This code will generate four figures, each containing the different types of plots you requested. The first figure is the 3D mesh graph, the second figure is the 3D surface graph, the third figure is the 3D surface graph with contour lines, and the fourth figure is the 2D sectional view graph for x=1. The ranges of the x and y axes are both [-1.2, 1.2], and the range of t is set to [-3, 3].