Yes, you can but I wouldn't recommend it. A 42 inch TV is over three times as big as a 24 inch monitor (4x as big as a 22") with the same resolution. If you were just watching videos you won't notice the difference, but if you're up close doing work you're going to see those big, ugly pixels.
http://www.displaywars.com/24-inch-16x9-vs-42-inch-16x9