[Turn] Matlab polynomial fitting

Turn: https://blog.csdn.net/hwecc/article/details/80308397

Example:

= x [ 0.33 , 1.12 , 1.41 , 1.71 , 2.19 ] 
y = [ 0.68 , 0.91 , 1.15 , 1.83 , 2.07 ]


 % fitted 
P1 = polyfit (x, y, 1 )% by fitting a polynomial of x and y, 1 represents a polynomial
                         % output   0.8025     0.2431 
                        % is represented by the polynomial F (X) = 0.8025 * X + 0.2431
 
% graphing 
Y1 = polyval (P1, X)         
Plot (X, Y, '*', x, y1, '-')