Why isn't my code graph anything.

Why don't matlab show me a graph. I ran it last time and it ran perfectly. Why nothing happend this time?

%create a cater plot
clear all;

%x = [20,30,40,50]
x = [-3,-1,1,2]
y = [8,23,28,34]
figure;
plot(x,y,"O",'MarkerSize', 4);
hold on
y=[8,23,28,34].'

colum = [1,1,1,1]

matrixA1 =[]

matrixA2 = []

matrixA3 = []

equation = (x -35)/ 5
%create a matrix
% first matrix
matrixA1 = [colum(:),x(:)]
% secon matrix
new_vector = x.^2
matrixA2 = [colum(:), x(:), new_vector(:)] 
% third matrix
new_vector3 = x.^3
matrixA3 = [colum(:), x(:), new_vector(:), new_vector3(:)] 

%create the tranpose matrix
tranposeA = matrixA1.';
tranposeB = matrixA2.';
tranposeC = matrixA3.';

% power 1
final_matrixA = [tranposeA*matrixA1 tranposeA*y];
%power 2
final_matrixB = [tranposeB*matrixA2 tranposeB*y];
%power e
final_matrixC = [tranposeC*matrixA3 tranposeC*y];

A1 =  rref(final_matrixA);
A2 = rref(final_matrixB);
A3 = rref(final_matrixC);

% for matrix A
a = A1(1,3);
b = A1(2,3);
%q = a+bx 
i = -10:10
q = a +b*i
plot(i,q)
hold on
% for matrix b
a1 = A2(1,4);
b1 = A2(2,4);
c1 = A2(3,4);

q1 = a1 +b1*i+c1*i.^2
plot(i,q1)
hold on
% matrix c
a2 = A3(1,5);
b2 = A3(2,5);
c2 = A3(3,5);
d2 = A3(4,5)

q2 = a2 +b2*i+c2*i.^2+d2*i.^3
plot(i,q2)

Answer 1

[Stephan]

Try:

%create a cater plot
clear all;

%x = [20,30,40,50]
x = [-3,-1,1,2]
y = [8,23,28,34]

y=[8,23,28,34].'

colum = [1,1,1,1]

matrixA1 =[]

matrixA2 = []

matrixA3 = []

equation = (x -35)/ 5
%create a matrix
% first matrix
matrixA1 = [colum(:),x(:)]
% secon matrix
new_vector = x.^2
matrixA2 = [colum(:), x(:), new_vector(:)] 
% third matrix
new_vector3 = x.^3
matrixA3 = [colum(:), x(:), new_vector(:), new_vector3(:)] 

%create the tranpose matrix
tranposeA = matrixA1.';
tranposeB = matrixA2.';
tranposeC = matrixA3.';

% power 1
final_matrixA = [tranposeA*matrixA1 tranposeA*y];
%power 2
final_matrixB = [tranposeB*matrixA2 tranposeB*y];
%power e
final_matrixC = [tranposeC*matrixA3 tranposeC*y];

A1 =  rref(final_matrixA);
A2 = rref(final_matrixB);
A3 = rref(final_matrixC);

% for matrix A
a = A1(1,3);
b = A1(2,3);
%q = a+bx 
i = -10:10
q = a +b*i

% for matrix b
a1 = A2(1,4);
b1 = A2(2,4);
c1 = A2(3,4);

q1 = a1 +b1*i+c1*i.^2

% matrix c
a2 = A3(1,5);
b2 = A3(2,5);
c2 = A3(3,5);
d2 = A3(4,5)

q2 = a2 +b2*i+c2*i.^2+d2*i.^3

% Plot
figure
hold on
plot(x,y,"O",'MarkerSize', 4);
plot(i,q,i,q1,i,q2)
hold off