How to plot curves with both option 'color' & dash line '--'

Hi Compose Experts,

I tried to plot curves with both option 'color' & dash line '--'. But it does not work and sometimes software crashes and suddenly shut down.

Thanks for your input and advice.

clc;
close all;

x = 0:0.1:30;
y1 = sin(x)
figure(1)
plot(x,y1)

y2=0.5*sin(x)
figure(3)
%hold on
plot(x,y2,'r','--')
xlabel ('t')
ylabel ('Signal')
title ('test sine curve')

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