How to change Navigationbar title irrespective of Tab title

I am setting the page title on the Navigationbar as

public Homework ()
{
   InitializeComponent ();
   Title = "Homework";     
}

This page is a child page of Tabbed page where the Tab already has the Title "Tab1".

Now when I open the Homework.cs page from Tab1, The above code changing Tab title to Homework and the Navigationbar title also changes to "Homework". I don't want to change Tab title.

MyTabbed page code using

   public class MyTabbedPage : TabbedPage
    {
        public MyTabbedPage()
        {
           this.CurrentPageChanged +=delegate
           {        
             this.Title = this.CurrentPage.Title;
           };     
        }
    }

See some convenient snippets

public App ()
{
    InitializeComponent();
    MainPage = new NavigationPage(new LoginPage());          
}

LoginContentPage button click

btnLogin.Clicked +=async delegate {
 await Navigation.PushAsync(new ParentDashboard(), false);
};

ParentDashboard Containing tabs

public partial class ParentDashboard : MyTabbedPage
{
    public ParentDashboard()
    {
        InitializeComponent();      
        Title="Home"; //upto here title working
    }
}

From now I am clicking on HomewPage as I shown in starting of this question & that is not working. How can I do this?