How can I plot the figure?

if true
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end

[Image Analyst]

In the future, please don't post questions that are homework without tagging them as homework. That way we can answer in a way that you can still guide you to the answer without giving it to you outright, and then requiring you to delete your question so you don't get into trouble with your professor.

[Myo Gyi]

Thank you sir.

Answer 1

[Image Analyst]

Is this homework?

Just use an two sets of code for the two ranges.

% First do the left range.
r1 = linspace(0, a, 500); % 500 points from 0 to a
z1 = ...your formula
plot(r1, z1, 'b-', 'LineWidth', 2);
% First do the right range.
r2 = linspace(a, 3, 500); % 500 points from a to 3
z2 = ...your formula
hold on;
grid on;
plot(r2, z2, 'b-', 'LineWidth', 2);
% Plot dashed line
line([1, 1], ylim, 'LineStyle', '--', 'Color', 'k');

[Image Analyst]

You didn't have the right equations. For example you didn't put parentheses around 2*g, so g ended up in the numerator instead of the denominator. And the equation for z2 was totally messed up. Fixed code is below:

% First do the left range.
w = 1;
a = 1;
g = 9.82;
r1 = linspace(0, a, 500); % 500 points from 0 to 
z1 = (w^2. * r1.^2) / (2*g);  % your formula
plot(r1, z1, 'b-', 'LineWidth', 2);
% First do the right range.
r2 = linspace(a, 3, 500); % 500 points from a to 3
term1 = (w^2 .* a.^2)/g;
term2 = 1 - a^2 ./ (2 * r2 .^ 2);
z2 = term1 .* term2;
hold on
grid on;
plot(r2, z2, 'b-', 'LineWidth', 2);
xlabel('r', 'FontSize', 25);
ylabel('z(r)', 'FontSize', 25);
% Plot dashed line
line([1, 1], ylim, 'LineStyle', '--', 'Color', 'k');
% Enlarge figure to full screen.
set(gcf, 'Units', 'Normalized', 'OuterPosition', [0, 0.04, 1, 0.96]);

[Myo Gyi]

Thank you very much sir.