Error using plot Vectors must be the same length

x1 = [0,3,6,9,12,15,18,21,24,27,30,33,36,39,41,44,47,50,53,56,59,62]; y1 = [1.4750,1.0873,0.7613,0.5446,0.3883,0.2920,0.1983,0.1416,0.1000,0.0710,0.0527,0.0360,0.0253,0.0186,0.0136,0.0093,0.0060,0.0041,0.0030,0. 0020,0, 0016,0.0010];
x2 = [0,3,6,9,12,15,18,21,24,27,30,33,36,39,41,44,47,50,53,56,59,62]; y2 = [0.3887,0.0837,-0.2731,-0.6077,-0.9460,-1.2658,-1.6180,-1.9547,-2.3026,-2.6451,-2.9431,-3.3242,-3.6770,-3.9846,-4.2977,-4.6777,-5.1160,-5.7763,-5.8091,-6.2146,-6.4377,-6.9077]
n = length(x); sumx=0.0; sumy=0.0; sumxy=0.0; sumxx=0.0;
for i=1:n sumx=sumx+x(i); sumy=sumy+y(i); sumxy=sumxy+x(i)*y(i); sumxx=sumxx+x(i)*x(i); end
%Determine Slope and y-intercept slope=(n*sumxy-sumx*sumy)/(n*sumxx-sumx^2); y_int=(sumxx*sumy-sumxy*sumx)/(n*sumxx-sumx^2);
z=slope*x+y_int;
%Making a plot loaded data plot(x1,y1,'bo',x,z,'r-') hold on Plot(x2,y2,’bo’,x,z,’r-‘) Hold off xlabel("time(s)") ylabel("v(t) v") %print('RC.png','-dpng')

%Errors di=y-(slope*x+y_int);

Error_in_slope=sqrt(sum(di.*di)*(n/(n-2))/(n*sumxx-sumx^2)); Error_in_y_int=sqrt(sum(di.*di)*sumxx*(n/(n-2))/(n*sumxx-sumx^2));

[VBBV]

vector y1 has more elements than x1, x2 and y2

declare the vectors x, y, ... are they same as x1 and y1 ...?

Then run the loop and plot it

[Walter Roberson]

Please reformat your code. Go into the editor and select the code and press the ">" button.... and then go through it and put in the appropriate line breaks, as we cannot assume which parts are really commented out and which just look to be commented out due to bad formatting.

Answer 1

[KSSV]

for i=1:n 
  sumx=sumx+x(i); 
  sumy=sumy+y(i); 
  sumxy=sumxy+x(i)*y(i); 
  sumxx=sumxx+x(i)*x(i); 
end

Toa chieve above you need not run a loop..you can achieve that using:

sumx = sum(x) ; 
sumy = sum(y) ;
sumxy = sum(x.*y) ; 
sumxx = sum(x.*x) ; 

Note that to get sumxy, the dimensions of x and y should be same.

[Sinethemba Galawe]

Thanks bro that helped