Question

Write a function in MATLAB called MYCURVEFIT that determines the y value of a best fit polynomial equation based on a single input, an x value. Predict the y value by fitting a 3rd order polynominal y=f(x) to the data points shown below. The input will be a single x value in the range of 0 to 20. The output should be a single y value obtained by evaluating the best fit third order polynomial at x.
X=0:0.5:20

Y=[14,16,18,22,28,35,50,68,90,117,154,200,248,309,378,455,550,654,770,900,1044,1200,1378,1560,...
1778,2004,2250,2500,2800,3100,3434,3786,4158,4555,4978,5424,5900,6401,6930,7474,8074]

You need to copy and paste the data above into your function

Answer 1

Solution:

The following will be used:

clc% clears screen

clear all% clears history

close all% closes all files

format long

MY CURVEFIT(7)

function y = MYCURVEFIT(x)

X = 0:0.5:20;

Y = [14, 16, 18, 22, 28, 35, 50, 68, 90, 117, 154, 200, 248, 309, 378, 455, 550, 654, 770, 900, 1044, 1200, 1378, 1560, 1778, 2004, 2250, 2500, 2800, 3100, 3434, 3786, 4158, 4555, 4978, 5424, 5900, 6401, 6930, 7474, 8074];

C = polyfit (X,Y,3);

y = polyval (C,x);

end