Figure but no plot

The code has no errors but won't show a plot, what am i doing wrong?

clear all, close all, clc

diffmax=100
x=0;0.1;diffmax

plot(f(x)) 
hold on

xlabel('x')
ylabel('velocity')

axis([0 diffmax 0 30])

function velocity=f(x)
    if x>75
        velocity = 25;
    else
        velocity = x/3;
    end
end

[Clara Holmén]

I have now changed the code bc the slope that was plotted was wrong. I created a matrix y to plot against x, instead of calling the function in plot(f(x). However the plot then disappeared again..

I have colons for x this time, have i missed something else?

clear all, close all, clc
matris=[]
diffmax=100
x=0:diffmax

for i=1:diffmax
    y=f(x(i))
    matris=[matris;y]
end

plot(x, y) 
hold on

xlabel('x')
ylabel('velocity')

axis([0 diffmax 0 30])

function velocity=f(x)
    if x>75
        velocity = 25;
        disp('rad 18')
    else
        velocity = x/3;
        disp('rad 21')
    end
end

Answer 1

[KSSV]

You have not defined f in your code...you need to define f and then call plot...something like this:

diffmax=100
x=0:0.1:diffmax ;
f = @(x) sin(x)
plot(x,f(x)) 

[Clara Holmén]

Thank you for the quick answer!

So it is not enough to have f as a function of x and have x defined??

[KSSV]

If you have defined an anonymous function (like in the answer), then you have to substitue it to get the function values for the given inputs.

[Clara Holmén]

ok ill try it!

[KSSV]

clear all, close all, clc

diffmax=100

diffmax = 100

x=0:0.1:diffmax

x = 1×1001

0 0.1000 0.2000 0.3000 0.4000 0.5000 0.6000 0.7000 0.8000 0.9000 1.0000 1.1000 1.2000 1.3000 1.4000 1.5000 1.6000 1.7000 1.8000 1.9000 2.0000 2.1000 2.2000 2.3000 2.4000 2.5000 2.6000 2.7000 2.8000 2.9000

●

plot(f(x)) 
hold on

xlabel('x')
ylabel('velocity')

axis([0 diffmax 0 30])

function velocity=f(x)
    if x>75
        velocity = 25;
    else
        velocity = x/3;
    end
end

Answer 2

[KALYAN ACHARJYA]

Here is the issue, the rest code is perfectly OK

x=0:0.1:diffmax
%..^ ..^ not semicolon, its colon

[KSSV]

Note that there is no f defined in the code.

[KALYAN ACHARJYA]

Sir, I dont think it is required, as f as function call within plot command. Can you share more please? Thanks

[Clara Holmén]

i have semicolons in my code, this snippet is from the answer from KSSV!

[KALYAN ACHARJYA]

@Clara Replace with colon in your original code, I have tried to answer this "

Figure but no plot

[KSSV]

Ohh yes, the function f is defined at the bottom. Just now I am having a look...I have copied only the first few lines..as the problem was in first line.

[Clara Holmén]

Sorry i misunderstood. It worked, thank you very much!!

[KALYAN ACHARJYA]

Hope your problem is resolved anyway.

Happy :)