Matlab plot not showing correct values
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Hi there,
Im trying to plot a graph using a for loop but the correct values are not being plotted. It is currently outputting the
same value 5 times. Any help would be appreciated.
clc;
clear;
hold on;
x=1:5;
grid on;
for i = 1:5
v=0.1553567*(i.^6)-2.0416*(i.^5)+9.1837*(i.^4)-14.829*(i.^3)-1.3703*(i.^2)+32.821*(i)-1.3155
end
plot(x,v,".")
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Answers (2)
Torsten
on 20 Oct 2022
v(i)=0.1553567*(i.^6)-2.0416*(i.^5)+9.1837*(i.^4)-14.829*(i.^3)-1.3703*(i.^2)+32.821*(i)-1.3155
instead of
v=0.1553567*(i.^6)-2.0416*(i.^5)+9.1837*(i.^4)-14.829*(i.^3)-1.3703*(i.^2)+32.821*(i)-1.3155
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dpb
on 20 Oct 2022
Edited: dpb
on 20 Oct 2022
No need for and don't use loops here...
p=[0.1553567,-2.0416,9.1837,-14.829,-1.3703,32.821,-1.3155]; % store poly coefficients as vector
x=1:5; % x range desired
y=polyval(p,x); % calculate y(p(x)) at x
plot(x,y,'*')
grid on;
Your problem above is you're calculating on value at a time in the loop, but not saving in an array and not plotting until after the loop has finished. Hence, the value is always the last iteration through the loop; you've written over the previous loop value each time the loop executes.
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