Are you thinking about a specific library? You aren't the only person who commented this way. But, the truth is that root, sin and so on don't "work" with floats either. In fact, there are common ways to implement these functions by either using tables (which are approximate) or algebraic approximations (that give you... drum roll: rationals!)
But, really, there isn't any way (except symbolically) to represent transcendental functions in computers. It doesn't matter what kind of number you choose to do it.
Are you thinking about a specific library? You aren't the only person who commented this way. But, the truth is that root, sin and so on don't "work" with floats either. In fact, there are common ways to implement these functions by either using tables (which are approximate) or algebraic approximations (that give you... drum roll: rationals!)
But, really, there isn't any way (except symbolically) to represent transcendental functions in computers. It doesn't matter what kind of number you choose to do it.