w=fminsearch (@q1,[2;-2;26])

x=[1,2,3,4,5,6,7,8,9,10];
y=[0,2,6,10,12,10,7,5,1,0];
plot(x,y)

N=1
  for r=min(x):1:max(x)
  if x(N) < 5
    y3(N)=10*x(N)*w(1) +w(2);
  elseif x(N) >= 5
   y3(N)=-10*x(N)*w(1) +w(3);
   endif
  N=N+1;
endfor	

hold on 
plot(x,y3)