function x = funcion2(t,k,a)
           %STAT Interesting statistics.
           x1 = -2*k*t+3+a;
           x2 = rectpuls(k*t+a-1.25,0.5); 
           x3 = rectpuls(k*t+a-0.5,1);
           x = x1.*x2 + x3;
           
 end