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NTA Abhyas JEE Main2020MathematicsFunctionsPractice

If e x + e f x = e , then the domain of the function f is

Options

  1. A- ∞ , 1
  2. B- ∞ , 1
  3. C- 1 , ∞
  4. D1 , ∞

Correct answer

B. - ∞ , 1

Step-by-step solution

We have, e x + e f x = e ⇒ e f x = e - e x ⇒ f x = log ⁡ e - e x For f x to be defined, e - e x > 0 ⇒ e 1 > e x ⇒ x < 1 ∴ Domain of f = - ∞ , 1

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