why my matlab didn't plot anything?

So i tried to plot a graph using this code, but it won't plot anything. I believe my code is plotting a point but not a line and i don't know why

clear all
m = 85

m = 85

g = 9.81

g = 9.8100

ti  = 0

ti = 0

tf1 = 9 

tf1 = 9

v(1)= -20

v = -20

h   = 1

h = 1

c1 = 11

c1 = 11

dv1 = @(g,c1,v,m) g-c1*v/m

dv1 = function_handle with value:
    @(g,c1,v,m)g-c1*v/m

while(ti<tf1)
    v = v + dv1(g,c1,v,m)*h
    ti = ti+h
    plot(ti,v)
    drawnow
end

v = -7.6018

ti = 1

v = 3.1920

ti = 2

v = 12.5889

ti = 3

v = 20.7698

ti = 4

v = 27.8919

ti = 5

v = 34.0924

ti = 6

v = 39.4904

ti = 7

v = 44.1899

ti = 8

v = 48.2812

ti = 9

Answer 1

[Matt J]

m = 85;
g = 9.81;
ti  = 0;
tf1 = 9 ;
v(1)= -20;
h   = 1;
c1 = 11;
dv1 = @(g,c1,v,m) g-c1*v/m;

k=1;
while(ti<tf1)
    k=k+1;
    v(k) = v(k-1) + dv1(g,c1,v(k-1),m)*h;
    ti=ti+h;
    plot(0:h:ti,v); drawnow
end

Answer 2

[DGM]

Start with something like this:

m = 85;
g = 9.81;
ti0 = 0;
tf1 = 9;
v0 = -20;
h = 1;
c1 = 11;
dv1 = @(g,c1,v,m) g-c1*v/m;

ti = ti0:h:tf1;
v = zeros(1,numel(ti));
v(1) = v0;
for k = 2:numel(ti)
    v(k) = v(k-1) + dv1(g,c1,v(k-1),m)*h;
end

plot(ti,v)

Plotting one point at a time is generally unnecessary and cumbersome. When you plot single points that way with the default linestyle, they are not connected by lines. You could make the dots themselves visible by specifying a marker type other than the default, but storing the results and putting the plot statement outside the loop avoids the hassle and leaves you with vectors that can be used for other things if needed.

It's also generally good to avoid unnecessary while loops, using for-loops when the number of iterations is known beforehand. This avoids any chance of mistakes or unpredicted scenarios that could cause the loop to not terminate. Such an oversight isn't really a big risk with something this small, but it's something to keep in mind as your code gets more complex.