Answer
Logarithms are only defined for positive numbers only. You can't define logarithms for negative numbers.
Work Step by Step
We know that exponential and logarithm functions are inverses of each other. Since they are inverses, the domain of exponential function is the range of logarithmic function, and the range of exponential is the domain of the logarithmic function. The domain of an exponential function is the set of all real numbers and its range is the set of all positive real numbers. Since the range of an exponential function is the set of all positive real numbers, the domain of the logarithmic function is all positive real numbers. Thus logarithms can be defined for positive numbers only. It is not possible to define logarithms for negative numbers.
