✔ 最佳答案
There is no problem with the fx-50FH. I think you get confused with the fx-50F Plus, which poses a problem with the authorities in that built-in formulae can be displayed. The fx-50FH omits this feature, which makes it allowable for use in open exams.
For you cause, I'm afraid your only choices of Casio models would be the fx-3650P and fx-50FH. The fx-3950P is the same as the 3650P but is battery-powered only and has a much shorter runtime, thus it's not recommended.
For technical highlights and specifications on these models, check out the following pages:
http://lpl.hkcampus.net/~lpl-wwk/Casio50/Casio.htm
http://lpl.hkcampus.net/~lpl-wwk/Casio50/FX50FPlus/FX50FPlus.htm