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domain of function f(x) = sqrt 2-2^x-2^2x. is ...what is the answer??

domain of function f(x) = sqrt 2-2^x-2^2x. is ...what is the answer??

Grade:12th pass

2 Answers

Deepak Kumar Shringi
askIITians Faculty 4404 Points
5 years ago
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Samyak Jain
333 Points
5 years ago
Let f(x) = \sqrt{}(2 – 2x – 22x)
The domain of f(x) can be found out by the following inequality : 
2 – 2x – 22x \geq 0  or  (2x)+ 2x – 2 \leq 0   Let 2= y
\therefore y2 + y – 2 \leq 0 ,  y+ 2y – y – 2 \leq 0
i.e. (y – 1)(y + 2) \leq 0
\therefore  y \epsilon ( – 2, 1)     \therefore   2x  \epsilon (– 2, 1),  which is incorrect \because 2is always positive (i.e. > 0) for x \epsilon R
\therefore  2x  \epsilon (0, 1).        This implies that x \epsilon ( – infinity , 0]

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