What's the problem?

I do not know what the code problem is for not plotting:

t=-50:1:50; y=(t.^2+9)/(t-3.^2); plot(t,y,'-k');

Answer 1

[Image Analyst]

You forgot to use dot slash to do an element by element divide:

t = -50 : 1 : 50;
y = (t.^2 + 9) ./ (t-3^2);
plot(t, y, 'k-', 'LineWidth', 2);
grid on;
xlabel('X', 'FontSize', 20);
ylabel('Y', 'FontSize', 20);

The above code works fine.

Answer 2

[Jonathan Chin]

I assume you wanted to do an element divide see small below

t=-50:1:50; 
y=(t.^2+9)./(t-3.^2); 
plot(t,y,'-k');