Matrix inside for loop not updating

Hi, I am trying to plot a function on a graph while in a loop but while my increment value is updating, my Y value data is not. My code is below, Thank you for Looking.

for t =1:1:200

g1(t)=3*cos(2*pi*450*t-141);

plot(t,g1(t),'.')

drawnow

end

Answer 1

[Torsten]

hold on
for t =1:1:200
    g1(t)=3*cos(2*pi*450*t-141);
    plot(t,g1(t),'.')
    drawnow
end

[Cooper Schenk]

i feel stupid now thank you!