I want to plot trend line (and want to record its slop) to multiple figures

Good Day, I have almost 50,000 points single column data. I divided it into 6 equal parts, calculated rms for each part, and want to plot trending curve of each part. For polyfit, I don't have values of x. I don't know why, but lsline is also not showing anything.

 T = 6*fix(numel(V1)/6);
six_parts = reshape(V1(1:T),[],6);
for i = 1:6
sp1= six_parts(:,i);
P1 = sp1;
Pa1 = WinSize*fix(numel(P1)/WinSize);    %numel(V1) counts number of elements in V1. it is numeL, not 1(one); fix(A) will round the number to nearest intiger
rP1 = rms(reshape(P1(1:Pa1),WinSize,[]),1);
figure;
% h1 = lsline
plot (rP1);
tmean(i) = trimmean(rP1,10)
xlswrite('abc',tmean);

Any suggestion is welcome

[KSSV]

YOu can take

x = 1:6 ;

[UET Hussain]

i tried this, but polyfit is not giving any output..... (means no trend line has been shown)

if true
  T = 6*fix(numel(N)/6);
six_parts = reshape(N(1:T),[],6);
for i = 1:6
sp1= six_parts(:,i);
x= 1:length(sp1);
x=x';
P1 = sp1;
Pa1 = WinSize*fix(numel(P1)/WinSize);    %numel(V1) counts number of elements in V1. it is numeL, not 1(one); fix(A) will round the number to nearest intiger
rP1 = rms(reshape(P1(1:Pa1),WinSize,[]),1);
figure;
plot (sp1);
polyfit(x,sp1,1);
tmean(i) = trimmean(sp1,10)
xlswrite('abc',tmean);
end

am i putting polyfit at right position????

[KSSV]

polyfit gives you slope and y-intercept of your straight line.....using these you need to draw you line.....you are not doing that....

Answer 1

[KSSV]

Use polyfit like below to draw a line later:

x = linspace(0,4*pi,10);
y = sin(x);
% Use polyfit to fit a line to the points

p = polyfit(x,y,1);
% Evaluate the polynomial on a finer grid and plot the results.

x1 = linspace(0,4*pi);
y1 = polyval(p,x1);
figure
plot(x,y,'o')
hold on
plot(x1,y1)
hold off

[UET Hussain]

thanks Sir, how to find the slop of that line, please?

[UET Hussain]

   slop = p(1); %Please see its "p", not "y1"
intercept = p(2);

[KSSV]

p = polyfit(x,y,1);

it has slope already....