how to code equation

I'm trying to code these equations. This is my attempt. I would like to plot Cf vs x/L, but x/L as I have it shows me an error..the same with delta/x, not sure why? any help will be greatly appreciated. Thanks much.

Re = 0:500:1000;
x/L = 0:0.2:1;
Cf = 0.664*(Re)^-0.5;
delta/x = 5.0*(Re)^-0.5;

[Les Beckham]

What are x, L, and delta?

Also, you can't put an expression like x/L on the left hand side of an assignment statement, only a variable name (optionally indexed).

Answer 1

[Sulaymon Eshkabilov]

Here is the corrected code:

Re = 0:50:1000;
xL = linspace(0,1, numel(Re));
Cf = 0.664*(Re).^(-0.5);
deltaX = 5.0*(Re).^(-0.5);
plot(Cf, xL, 'ro', 'markerfacecolor', 'y')
xlabel('C_f')
ylabel('x_L')
grid on

[Cesar Cardenas]

Thanks much for your help. Just a quick question, I coded this simple equation. I got a plot. It shows a straight line, buyt I think it should be some kind of curve, is it right? or is there is something wrong? Thanks.

Ue = @(x)2*(1-x);
x = (0:0.1:1);
plot(Ue(x),x)
grid on

[Walter Roberson]

syms x
Ue(x) = 2*(1-x)

Ue(x) = 

diff(Ue,x)

ans(x) = 

The derivative of the function is constant; therefore the function must be a straight line, not a curve.

[Cesar Cardenas]

Hello I would like to plot, q, h and Re in the same graph, no sure about it, any help will be appreciated. Thanks

1 = 30;
T2 = 40;
v = 0.5;
x1 = 0.01;
x2 = 0.05;

Pr = 5.18;
nu = 7.708;
k = 0.6184;
d =  995;

Re = v*(x2-x1)/nu
h = 0.3314*(Re.^(0.5))*(Pr.^(0.3))*(k/x2 - x1)
q = h*(x2 - x1)*1*(T2-T1)

plot (h, q, Re)

[Walter Roberson]

Your h, q, and Re are all scalars, so plotting them on the same graph is not going to be interesting.

T1 = 30;
T2 = 40;
v = 0.5;
x1 = 0.01;
x2 = 0.05;

Pr = 5.18;
nu = 7.708;
k = 0.6184;
d =  995;

Re = v*(x2-x1)/nu

Re = 0.0026

h = 0.3314*(Re.^(0.5))*(Pr.^(0.3))*(k/x2 - x1)

h = 0.3417

q = h*(x2 - x1)*1*(T2-T1)

q = 0.1367

plot([h, q, Re],'r*')