I want to create a sin wave pulse function y(t) that has exponential damping, but I get this error "Array indices must be positive integers"

This is the code I have, Any ideas why I'm getting this error? I am a college student and just started working with matlab

A=4

a=exp(-0.5*t)

y(t)=A*a(sin(2*pi*3*t)).*(ustep(t+1)-ustep(t-1))

t=linspace(-2,2)

y(t)=linspace(-4,4)

plot(y(t))

Answer 1

[Image Analyst]

I don't have the ustep() function, but I think this is closer than what you have:

A = 4
t = linspace(-2, 2, 1000);
a = exp(-0.5*t)
y = A * a * (sin(2*pi*3*t)) .* (ustep(t+1)-ustep(t-1))
plot(t, y, 'LineWidth', 2)
xlabel('t');
ylabel('y');
grid on;

[Roberto Santana]

Thank you so much !