for k=1:100if k<3x(k)=0.01*k;f(k)=1;else if 2<k<100x(k)=0.01*k;f(k)=f(k-2)+2*0.01*10000*(ppval(cs,(k+1)*0.01)+ppval(cs,(k-1)*0.01)-2*ppval(cs,k*0.01));elsex(k)=0.01*k;f(k)=1;end;end;plot(x,f)