How to predict using interpolation or polyfit

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Mekala balaji 2017-9-13

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回答： Akira Agata 2017-9-13

采纳的回答： Akira Agata

Hi, I have data as below:

x y 1.2 2.3 4.8 2.7 5.8 3.5

and I want to predict for x is 2.7, what is y? Many thanks in advance,

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KSSV 2017-9-13

YOu have given only one value....provide both x and y....read about interp1

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Akira Agata 2017-9-13

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https://ww2.mathworks.cn/matlabcentral/answers/356490-how-to-predict-using-interpolation-or-polyfit#answer_281386

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...Or polyfit function, like:

xy = [1.2, 2.3;
  4.8, 2.7;
  5.8, 3.5];
p = polyfit(xy(:,1), xy(:,2), 2);
x = linspace(0,6);
y = polyval(p, x);
figure
plot(xy(:,1), xy(:,2),'ro');
hold on;
plot(x,y,'b:');
plot(2.7, polyval(p, 2.7), 'bo');
legend({'Data','polyfit','estimated value at x = 2.7'});