Plotting multiple equations in one plot

I am trying to create my own plot of the following and can't seem to get it right. I can't figure out how to plot the equations for both r and 1/l, I only seem to plot an equation for either r or 1/l.

I used 'linspace' to get an even 100 points for both r and 1/l.

The equations I'm trying to plot are as follows:

V/c = ln(l) - (1/r)*(1-1/l), for V/c = 0.5 & 1

nmax + 1 = r*l, for nmax+1 = 8 & 4

tb/Isp = (1/r)*(1-1/l), for tb/Isp = 1 & 0.5

Any help would be greatly appreciated!

[Benjamin Thompson]

Can you post your work so far? Are you using "hold on" to let the plot take a second set of data?

[Gavin Hutchins]

My code has changed quite a bit trying to complete this, but this is what I most recently tried.

r = linspace(0,7);

l = linspace(0,1);

V_c = log(1./l)-(1./r).*(1-l);

nmax = r.*(1./l);

tb_Isp = (1./r).*(1-l);

plot(l,V_c)

hold on

plot(l,nmax)

hold on

plot(l,tb_Isp)

I'm not sure how to plot the 3 equations for each of their 2 specified values, also not sure how to get the y-axis to be 'r' and x-axis to be '1/l'

[Benjamin Thompson]

You would use

plot(1./l, r)

The vectors for l and r must be the same length. You cannot have a value of zero in l when you calculate 1/l of course.

Answer 1

[David Hill]

L=.01:.01:1;
count=1;
for v=[.5 1]
   r(count,:)=(1-L)./(log(1./L)-v);
   count=count+1;
end
for n=[8 4]
    r(count,:)=n*L;
    count=count+1;
end
for tb=[1 .5]
    r(count,:)=(1-L)/tb;
    count=count+1;
end
plot(L,r);

[Gavin Hutchins]

I appreciate the help, thank you!