Java BigDecimal trigonometric methods

ApFloat is a library which contains arbitrary-precision approximations of trigometric functions and non-integer powers both; however, it uses its own internal representations, rather than BigDecimal and BigInteger. I haven't used it before, so I can't vouch for its correctness or performance characteristics, but the api seems fairly complete.

BigDecimal does not provide these methods because BigDecimal models a rational number. Trigonometric functions, square roots and powers to non-integers (which I guess includes square roots) all generate irrational numbers.

These can be approximated with an arbitrary-precision number but the exact value can't be stored in a BigDecimal. It's not really what they're for. If you're approximating something anyway, you may as well just use a double.

The big-math library provides all the standard advanced mathematical functions (pow, sqrt, log, sin, ...) for BigDecimal.

https://github.com/eobermuhlner/big-math