Godot Platformer - Throwing projectiles - How to make it land in a certain point

Please I need your help to figure this out.

I have this formula that I have been trying to apply to my project.

I use the GoDot engine to create a 2D platformer game with projectiles.

static public Vector2 calculate_arc_velocity(Vector2 point_a, Vector2 point_b, float arc_height,float up_gravity=30, float? down_gravity=null)

{

   if(down_gravity==null)
       down_gravity=up_gravity;
   Vector2 velocity = new Vector2();
   Vector2 displacement = point_b-point_a;
   //GD.Print(displacement);
   if(displacement.y>arc_height)
   {
       var time_up = Mathf.Sqrt(-2F*(float)arc_height/(float)up_gravity);
       var time_down = Mathf.Sqrt(2F*((float)displacement.y-(float)arc_height)/(float)down_gravity);
       velocity.y = -Mathf.Sqrt(-2F*(float)up_gravity …