To make things more complex, the same function can have transcendental/algebraic number answers depending on the domain. For example, sin (1 radian) is transcendental, while sin (1 degree) is algebraic.
Since e is transcendental, ln a (where a is not equal to 0 or 1 and is algebraic) is also transcendental.
A fundamental problem about transcendental numbers that still needs to be proved is whether a^b, where a is not equal to 0 or 1 and is algebraic and b is algebraic but not rational, is always transcendental.