What is ln(0)?

The natural logarithm of 0, denoted as ln(0), is undefined. This is because the natural logarithm is the inverse function of the exponential function and it does not exist for non-positive numbers. In other words, the logarithm function requires a positive number as its input. When the input is 0, the logarithm function cannot be evaluated because there is no number that can be raised to a power to give 0. Therefore, ln(0) is considered undefined in mathematics.