Drawing lines in a loop

Dear all,

I am searching for a way to draw multiple lines in a "for", or "while" loop. This is what I tried so far:

plot(xa,phi(xa),'b',x,eta(x),'b')

hold on

syms xls yls

yls = 0.004;
xls = 0.0001;

while xls ~= width,

startp = [xls yls];
endp = [xls eta(xls)];

Xl = [startp(1) endp(1)];
Yl = [startp(2) endp(2)];

line(Xl, Yl); 
xls = xls + 0.0001;

end

As you can see, I am trying to draw vertical lines in a plot showing a function. These vertical lines should end exactly where they intersect the function...

I am quite stuck with this problem and I would very much appreciate it if someone could help me!

Kind regards, Marc

[the cyclist]

I can't run your code, so I can't actually see the problem exhibited. Can you please describe in more detail what the actual problem is?

Answer 1

[Azzi Abdelmalek]

%Example
close
x=0:0.1:10
y=sin(x)./(x+0.1)
plot(x,y)
hold on
x_line=[0 2 4 6 8 10]   % The x coordinate intersecting the vertical lines
y_line=interp1(x,y,x_line)
y_lim=get(gca,'ylim');
ymax=y_lim(2);
for k=1:numel(x_line)
  plot([x_line(k),x_line(k)],[y_line(k) ymax],'r')
end
hold off

[Marc]

thank you!