Differentiation Question 306

Question: If $ y={\log_2}[{\log_2}(x)] $ , then $ \frac{dy}{dx} $ is equal to

Options:

A) $ \frac{{\log_2}e}{x{\log _{e}}x} $

B) $ \frac{1}{{\log _{e}}x{\log _{e}}2} $

C) $ \frac{1}{{\log _{e}}{{(2x)}^{x}}} $

D) None of these

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Answer:

Correct Answer: A

Solution:

$ y={\log_2}[{\log_2}(x)]={\log _{e}}({\log _{e}}x.{\log_2}e).{\log_2}e $

$ =[{\log _{e}}{\log _{e}}x+{\log _{e}}({\log_2}e)]{\log_2}e $

$ \therefore \frac{dy}{dx}={\log_2}e.\frac{1}{x{\log _{e}}x} $ .