WBJEE · Maths · Functions
The function \(f: \mathbb{R} \rightarrow \mathbb{R}\) defined by \(f(x)=e^x+e^{-x}\) is
- A one-one
- B onto
- C bijective
- D not bijective
Answer & Solution
Correct Answer
(D) not bijective
Step-by-step Solution
Detailed explanation
\(\begin{aligned} & \text { Hint: } \because \mathrm{f}(\mathrm{x}) \text { is even function } \quad \therefore \text { Not one-one } \\ & \because \mathrm{e}^{\mathrm{x}}+\mathrm{e}^{-\mathrm{x}} \text { can't be negative } \quad \therefore \text { Not onto }\end{aligned}\)
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