param N := 4;

var x{1..N};


minimize f:
100*(x[2] - x[1]^2) + (1-x[1])^2 + 90*(x[4]-x[3]^2) + (1 - x[3])^2 + 10.1*((x[2] - 1)^2 + (x[4] - 1)^2) + 
19.8*(x[2]-1)*(x[ 4]-1);

data;
var x:=
1	-3
2	1
3	-3
4	1;

solve;

display x;