Relations Question 15

Question: Which pair of functions is identical?

Options:

A) $ {{\sin }^{-1}}(sinx)andsin(si{n^{-1}}x) $

B) $ {\log _{e}}e^{x},{e^{{\log _{e}}x}} $

C) $ {\log _{e}}x^{2},2log _{e}x $

D) None of these

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Answer:

Correct Answer: D

Solution:

Here,

(1) $ {{\sin }^{-1}}(\sin x) $ is defined for $ x\in [ -\frac{\pi }{2},\frac{\pi }{2} ] $ , while $ \sin (si{n^{-1}}x) $ is defined only for $ x\in [-1,1] $

(2) $ {\log _{e}}e^{x}, $ is defined for all x, while $ {e^{{\log _{e}}x}} $ is defined for $ x>0. $

(3) $ {\log _{e}}x^{2} $ is defined for all $ x\in R-{0} $ , while $ 2{\log _{e}}x $ is defined for $ x>0. $

Thus, none is identical.