Add forward slash at end of root domain

Hi,
How can I add a forward slash at the end of root domain? http://www.example.com/

Under Permalink, I made it /%postname%/ ,this added the slash at the end of posts, pages, this is good.

However, I could not make the slash appear on home page, I want to http://www.example.com/ instead of http://www.example.com

I tried to edit htaccess many times, non of the code worked.

Please help, thanks a lot.