param N := 4;

var x{1..N};

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

subject to cons1:
x[4] <= 1;

data;
var x:=
1	0
2	0
3	0
4	0;


solve;

display x;