Q: i have several copies of my photos on my ipad under photos not photo stream    There is no delete button when I tap the duplicate photos.  How do I delete these pleas?

Before deleting anything be sure they are actually duplicate photos.  If you create an album on your phone, then add photos to it from your camera roll, the photos in the album are not duplicates; they only contain links to the actual photos in camera roll.  (Albums are like music playlists; they don't contain the actual photo but just a link to it so that you can look at a subset of your photos.)  Thus, if you delete the photo from the camera roll it will be deleted from all albums that may have contained it (just as a song would be deleted from any playlist that contained it if you deleted the song from your music library).

Similarly, photos synced to your iPad from your computer are all contained in the photo library.  Just like albums created on your phone, any albums synced to your phone will only contain links to the actual photos in the photo library.  If you delete the photo from the photo library, it will be deleted from any albums that may contain it as well.  This video may help explain this: http://www.youtube.com/watch?v=60MevRF53ck&feature=channel&list=UL.

All that said, you can delete photos from the camera roll by either opening them individually and tapping the trash can icon, or by opening the camera roll in the thumbnail view, tapping Edit, tapping all the photos you want to delete, then tapping the Delete button at the bottom.   To delete photos synced to your iPad from your computer you have to delete them by connecting your iPad to your computer, going to the Photos tab of your iTunes sync settings, unchecking the photos you no longer want on your iPad, then syncing.  Photos in photo stream are deleted by opening the photo, then tapping the trash can icon.