Trigonometer

This is my first application. What's curious I made it 100% on my own! Just had a need to get trigonometric values on the simplest way. But I didn't have any experience in Obj-C and Xcode. I spent one weekend to learn basics and try some methods/objects that I would need to complete my idea. At the next weekend I drew this app (in about 2-3 hours) and were trying to implement it.
In fact I did this application in two weekends with no previous knowledge how to do :)
My friend recommended me to send it to the AppStore. Thereby my small iOS lab got a new extra product.
Application is already now available here:
http://itunes.apple.com/us/app/trigonometer-trigonometry/id505865947

Feel free to write some words what do you think about interface and UX issues.