function convol=convolucion(func,func2,a,b);
close all;
funcion = str2func(func); 
funcion2 = str2func(func2);
figure;
hold on; 
 h=a:0.01:b;f=funcion(h);
 h2=(-b-a):0.01:(b-a);f2=funcion2(h2);
 plot(h,f,'b','LineWidth',2);axis('square');xlabel('x(t)');pause
 plot(h2,f2,'r','LineWidth',2);axis('square');xlabel('x(t) y h(t)');
hold off;
pause(3);
t=(a-0.5):0.01:(b+0.5); 
convol = repmat(double(0), [1 length(t)]);
for k=1:1:length(t);
     convo_kx = @(x) funcion(x).* funcion2(t(k)-x);  
        convol(k) = quadl(convo_kx, a, b);     
end
figure;
hold on;
plot(t,funcion(t),'b','LineWidth',2);axis('square');
plot(t,funcion2(t),'r','LineWidth',2);axis('square');
plot(t,convol,'g','LineWidth',2);axis('square');xlabel('(x*h)(t)');
hold off;