A DESCRIPTION OF THE PROBLEM :
BigDecimal and BigInteger come with basic functionalities like adding, dividing - similar to the operations +, / in the java language for double or int.
But both lack additional functionalities that are available for double in java.lang.Math like sin() or have restrictions on those functionalities e.g. BigDecimal.pow() only works with integers while Math.pow() works with doubles.

Please provide additional functionality in BigDecimal and BigInteger or (better) provide a java.lang.Math helper-class for BigDecimal and BigInteger with all functionalities of java.lang.Math.

Cornell University has some (no longer maintaines) OS-implementations for those - see https://arxiv.org/src/0908.3030v3/anc