If you have the iPad 2 or later, you can connect wirelessly to an external display, like a TV, so that everyone can see the same screen. To connect wirelessly, you must have the second generation (or higher) AppleTV that is then connected via HDMI to your screen. The iPad connects wirelessly to the AppleTV box which then displays your music on the TV.
Set up AirPlay Mirroring to your AppleTV
- Swipe up from the bottom of the screen to open up the iPad's "Control Center" (For more details see: http://www.apple.com/ios/ios7-basics/)
- Tap "AirPlay" (If you don't see the AirPlay button, your iPad and AppleTV are probably not on the same WiFi network.)
- Select your AppleTV
- Switch on "Mirroring" to make your TV or projector present an external display of your pdfs. (If Mirroring isn't an option, make sure you have the second generation AppleTV or later, or the iPad2 or later and that they've been updated to the most recent software.)