I am a total beginner with Xcode and Objective C, but I have some experience with OOP in C++. I bought this https://rads.stackoverflow.com/amzn/click/com/067233576X book. I read about how to make a simple app, and skimmed the rest of the book. What I want to do is make an iPhone app people can use to look up math equations such as the quadratic eqauation, pythagorean identity, etc. I plan to include a lot of stuff, and do a lot of things better than other apps I have seen. However, before I pay Apple $99 to be a full fledged iOS developer, I want to know that it isn't too hard to make the Greek letters and Math notation that we see in math books. So for example, what code is needed to make an iPhone app that display 
. Of course I want to use features that I understand are included in Xcode for doing this sort of thing, rather than, make a graphic with another program that my app would use when needed. Besides that specific example, where is the Apple documentation for making other math symbols and notation that my iPhone app will display? If this is the wrong place to ask, it would be great if you could tell me of a beter place to post my question.
需要大量编写才能使用系统框架获得良好的布局。所有构建块都在那里，但您的程序需要大量的渲染自定义才能获得您期望的布局。具体来说，您需要的字符已经存在，但您需要编写一堆支持代码才能正确调整这些字符的大小、位置和布局。
您可能需要寻找一个可以使用的、专门用于此目的的获得适当许可的库。也许 LaTeX 渲染器会提供一些好的线索。
