Q: I can't airplay my iPad 2

About AirPlay and Airplay Mirroring

AirPlay Mirroring requires a second-generation Apple TV or later, and is supported on the following Mac models: iMac (Mid 2011 or newer), Mac mini (Mid 2011 or newer), MacBook Air (Mid 2011 or newer), and MacBook Pro (Early 2011 or newer). For non-qualifying Macs you can try using Air Parrot.

Several Apple Articles Regarding AirPlay

Apple TV (2nd and 3rd gen)- How to use AirPlay Mirroring

How to set up and configure AirPort Express for AirPlay and iTunes

About AirPlay Mirroring in OS X Mountain Lion

iTunes 10- About playing music with AirPlay

Troubleshooting AirPlay and AirPlay Mirroring

Using AirPlay

Thanks to the $15 Beamer, AirPlay streaming is still possible on Macs  that do not support Airplay and mirroring.

Another solution is the Air Parrot.

No .... seeing as how the response listed out the iMac models that support AirPlay, the real question should be, "Do you or do you not have one of those?"

Pardon the English major, here, but I would reword the question to read:

Can I share my iPad screen on my iMac without an Apple TV?

I recommend you might create a new topic with that question. I don't know the answer. All I have about Airplay is what I have already posted. From the article titles I don't think you need an Apple TV, but I may be wrong.