function q = q1(a)
	
x=[1,2,3,4,5,6,7,8,9,10];
y=[0,2,6,10,12,10,7,5,1,0];
N=1
  for r=min(x):1:max(x)
  if x(N) < 5
    y1(N)=10*x(N)*a(1) +a(2);
  elseif x(N) >= 5
   y1(N)=-10*x(N)*a(1) +a(3);
   endif
  N=N+1;
endfor	
y2 = (y-y1).^2
q=sum(y2)
a
endfunction