“Is there an easy way to take an iPad screenshot without installing a screen capture app on my iPad?”
Starting with iOS 2.0, Apple made it easy to take iPhone screenshots without additional software. Taking an iPad screenshot is just as easy because the steps are identical. You simply need to hold down the home button, the press the sleep/wake button at the same time. Once you grab the iPad screenshot it will appear in your Photos on the iPad. Once you have the iPad screenshot emailing is just as easy.

If you have your email configured on your iPad, you can very quickly email a screenshot by attaching the screenshot stored in your Photos to an email message, just like you would any other attachment. If you never use email on your iPad, you will need to connect your iPad to the computer you sync with, copy the screenshot off your iPad and follow the steps you use to attach an image to an email message in your email software.