Matlab - Interporacion cuadratica

clear

   x=[0        3               4.5           7.5            10.5              14              16                 19              22.5         24     25          25.5     27];

   y=[0      -900       -3000       3900           -500             5400        -900             3900          -3000         -1100    -1000       -500         0   ];

    whos x y

plot(x,y,'o')

hold on

for i=1:4:10

p = polyfit(x(i:i+4),y(i:i+4),4);

x1 =linspace(x(i),x(i+4));

y1 =  polyval(p,x1);

figure(gcf)

plot(x1,y1,'r')

axis('ij')

end

hold off

grid on

clear

x=[0 1.5 4.5 7.5 10.5 13.5 16.5 19.5 22.5 25.5 27]

y=[0 453.6 3040 -3592.8 404.29 -5339.9 404.29 -3592.8 3040 453.6 0]

    whos x y

plot(x,y,'o')

hold on

for i=1:4:length(x)-3

p = polyfit(x(i:i+4),y(i:i+4),4);

x1 =linspace(x(i),x(i+4));

y1 =  polyval(p,x1);

figure(gcf)

plot(x1,y1,'r')

axis('ij')

end

hold off

grid on