I've tested ~20 or so free calculators from the Play store but still have not found what I was looking for...
- Runs on Android 5
- Calculations are done offline
- Free (ad-supported is ok, but ad-free preferred)
- Should not require any ROMs from real calculators (so Andie Graph is not an option, although the TI-63 can fulfill all those requirements)
- Can calculate trigonometric functions in Degrees
- Has a calculator-like keypad, i. e. I don't have to type s,i,n on a QUERTY keyboard to get
- Can convert results to fractions (if they can be converted, of course)
- Bonus if this also works for fractions of square roots (if not, I can square myself and convert to fractions)
- Acceptable precision (i. e. does not trip over its own feet when trying to convert to fraction because of precision loss before)
- Bonus if it can graph functions, show the input formula in mathematical notation, or detect more things in the results automatically (e. g. prime factors, cube roots).
Test expressions (yes each of them fails even in the decimal expansion on some of the tested calculators):
22 / 7 * 7 - 22= 0
sin (60)^2= 3/4