Question Detail
Question
Evaluate lim x→0 (ax - 1) / x
Correct Answer
Option B is the correct answer.
Detailed Explanation
This is a standard limit that defines the derivative of the function f(x) = a^x at x = 0.The definition of the derivative f'(c) is limx→c (f(x) - f(c)) / (x - c).Here, f(x) = a^x and c = 0.So, limx→0 (a^x - a^0) / (x - 0) = f'(0).We know that the derivative d/dx (a^x) = a^x ln a (or a^x log_e a).Therefore, f'(0) = a^0 ln a = 1 * ln a = ln a.In higher mathematics, 'log a' often refers to the natural logarithm (ln a) when the base is not specified.
Hint
Recall the definition of the derivative from first principles or use L'Hopital's rule. The derivative of a^x is a^x ln a.