x = [0 rand(1,100)*20 20];
x = sort(x);
x = x';
y = abs(sin(x))+(rand()*5)+2;

 distance = trapz(x,y)

 fit1 = fit(x, y, 'poly7')
 aprox1 = feval(fit1, x);


cvalues = coeffvalues(fit1);
cnames = coeffnames(fit1);
output = formula(fit1);

for ii=1:1:numel(cvalues)
    cname = cnames{ii};
    cvalue = num2str(cvalues(ii));
    output = strrep(output, cname , cvalue);
end

output = strrep(output, '^', '.^')


fhandle = @(x) (output)


 distance = integral(fhandle, 0, 20)

 plot(x, y, 'r', x, aprox1, 'b')