What happened if the base of exponential function is less than zero?

If the base of an exponential function is less than zero, the function can exhibit complex behavior. Specifically, if the base is a negative number, the function will not be defined for all real numbers, as it will yield complex numbers for non-integer exponents. Consequently, the exponential function may oscillate between positive and negative values, depending on the exponent's parity, which complicates its interpretation in real-world applications. Thus, exponential functions are typically defined with a positive base for meaningful real-valued outputs.