zooming out of a signal?

Can anyone help me zoom out or change the window size? Because the signal I'm using creating a blue box because of the high frequency.

f=400;
ts=1/8000; 
T=5; 
t=0:ts:T; 
y=sin(2*pi*f*t);
plot(t,y)

Answer 1

[Azzi Abdelmalek]

Reduce the value of T

f=400;
ts=1/8000; 
T=0.01; 
t=0:ts:T; 
y=sin(2*pi*f*t);
plot(t,y)