How to make a rainbow in MatLab?

Hello can someone please help me work this out? My professor asked us to make a rainbow. This is what I have so far, using the trajectory problem that we've been working the whole semester. The point is to make each arc of different colors (roygbiv), . What I got is just one arc with multiple colors. Please help!!!

format compact
Xo=0;
Yo=0
t=0;
inch=.01;
X=0;
Y=0;
theta=45;
V=5;
g=-9.8
hold on
while X==0 | Y>0
   X=Xo+V.*cosd(theta).*t;
   Y=Yo+V.*sind(theta).*t+0.5.*g.*t.*t;
   fprintf('t=%4.3f X=%4.2f Y=%4.3f\n',t,X,Y)
   t=t+inch;
   pause(0.1)
   plot(X,Y,'*')
   axis([0,3,0,1])  
end

hold off

Answer 1

[Akira Agata]

One possible way:

t = linspace(0,pi)';
x = cos(t);
y = sin(t);
color = jet(7);

figure
hold on
for kk = 1:7
  plot((2+kk)*x,(2+kk)*y,'Color',color(kk,:),'LineWidth',20)
end
ylim([0 15])

Another possible solution:

[xGrid,yGrid] = meshgrid(-10:0.1:10,0:0.1:10);
zGrid = sqrt(xGrid.^2 + yGrid.^2);

figure
surf(xGrid,yGrid,zGrid,...
  'EdgeColor',  'none',...
  'FaceAlpha',  0.5)
colormap(jet)
set(gca,'CLim',[4 11])
zlim([5 10])
view(2)

I hope you enjoy these codes ! :-)

[Juan Zegarra]

thank you so much!!