param N := 3;

var x{1..N};

param t{i in 1..10} := 0.1*i;

minimize f:
sum {i in 1..10} ((exp(-1*x[1]*t[i]) - exp(-1*x[2]*t[i])) - x[3]*(exp(-1*t[i]) - exp(-10*t[i])))^2;

subject to cons1{i in 1..N}:
0 <= x[i] <= 10;

data;
var x:=
1	2.5
2	10
3	10;
solve;

display x;