As their names imply, BigInteger and BigDecimal are meant to be used for arbitrarily large numbers. Unless, you are using numbers that are over 9*10^19 (the maximum value for a long), then you should probably just use the built-in types like double and long. The Math class from the standard API provides methods to perform just about any mathematical operation you need. These include the basic trigonometric functions and logarithms, to name a few.
The soul is dyed the color of its thoughts. Think only on those things that are in line with your principles and can bear the light of day. The content of your character is your choice. Day by day, what you do is who you become. Your integrity is your destiny - it is the light that guides your way. - Heraclitus