Functions Question 61

Question: $ \underset{x\to 0}{\mathop{\lim }},( \frac{a^{x}-b^{x}}{x} )= $

[EAMCET 1988; RPET 1995]

Options:

A) $ \log ( \frac{b}{a} ) $

B) $ \log ( \frac{a}{b} ) $

C) $ \frac{a}{b} $

D) $ \log a^{b} $

Show Answer

Answer:

Correct Answer: B

Solution:

$ \underset{x\to 0}{\mathop{\lim }}\frac{a^{x}-b^{x}}{x}=\underset{x\to 0}{\mathop{\lim }}( \frac{a^{x}-1}{x} )-\underset{x\to 0}{\mathop{\lim }}( \frac{b^{x}-1}{x} ) $ $ =\log a-\log b=\log ,(a/b) $ .