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A simpler description:
We know that we can only take the lo g of positive numbers x > 0 . Therefore:
The domain of f ( x ) = 2 lo g x is 0 < x < ∞ or ( 0 , ∞ ) , whichever notation you prefer.
Now, remember that x 2 ≥ 0 for all real values of x
This means that besides x = 0 , any other value of x will give us a positive value for x 2 , whose lo g can be calculated. Therefore:
The domain of f ( x ) = lo g ( x 2 ) is − ∞ < x < ∞ , x = 0 or ( − ∞ , 0 ) ∪ ( 0 , ∞ )
Therefore, the domains of f ( x ) = 2 lo g x and f ( x ) = lo g ( x 2 ) are not the same, and the answer is No