Differentiation Question 246

Question: If $ y={\log _{10}}x+{\log _{x}}10+{\log _{x}}x+{\log _{10}}10, $ then $ \frac{dy}{dx}= $

Options:

A) $ \frac{1}{x{\log _{e}}10}-\frac{{\log _{e}}10}{x{{({\log _{e}}x)}^{2}}} $

B) $ \frac{1}{x{\log _{e}}10}-\frac{1}{x{\log _{10}}e} $

C) $ \frac{1}{x{\log _{e}}10}-\frac{{\log _{e}}10}{x{{({\log _{e}}x)}^{2}}} $

D) None of these

Show Answer

Answer:

Correct Answer: A

Solution:

$ y={\log _{10}}x+{\log _{x}}10+{\log _{x}}x+{\log _{10}}10 $

$ ={\log _{10}}x+\frac{{\log _{e}}10}{\log x}+1+1 $

$ \Rightarrow \frac{dy}{dx}=\frac{1}{x}{\log _{10}}e-\frac{{\log _{e}}10}{x{{({\log _{e}}x)}^{2}}} $ .