UPDATE 2 - Thank you everyone for the good reviews! I am very flattered. I love the idea that I am helping other math/engineering students around the world! This app will always be free, but please consider donating if you like it! Bitcoin address: 1PuhR83yykTsjhgqraY8A6X4YKSeUgCk7J. Much wow. Such appreciation. Dogecoin address: DAxBZKeXq8MKeH2wphN1HLff26Gdc8K2fn.