param N := 3;

var x{1..N};

minimize f:
log(x[3]) - x[2];

subject to cons1:
x[2]^2 + x[3]^2 - 4 = 0;

subject to cons2:
x[3] - 1 - x[1]^2 = 0;

data;
var x:=
1	1
2	1
3	1;
solve;

display x;