This Function show you how to use Union to create one sequence that contains the unique values from both arrays.
public void UnionExample()
{
int[] A = { 1,2,3,4,2,1,3,5,4,6,4,2,1,9 };
int[] B = { 1, 3, 5, 7, 8,4,10,11 };
var uniqueNumbers = A.Union(B);
Console.WriteLine("Unique numbers from both arrays:");
foreach (var n in uniqueNumbers)
{
Console.WriteLine(n);
}
}