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Question: Answered & Verified by Expert
The function $f: R \rightarrow R$ defined by $f(x)=\left(x^{2}+1\right)^{35}$ for all $x$ $\in R$ is
MathematicsFunctionsNDANDA 2008 (Phase 2)
Options:
  • A one-one but not onto
  • B onto but not one-one
  • C neither one-one nor onto
  • D both one-one and onto
Solution:
2315 Upvotes Verified Answer
The correct answer is: neither one-one nor onto
$f(-1)=f(1)=2^{35}$
Here, two real numbers 1 and $-1$ have the same image. So, the function is not one-one and let $y=\left(x^{2}+1\right)^{35}$
$\Rightarrow x=\sqrt{(y)^{1 / 35}-1}$
Thus, every real number has no pre image. So, the function is not onto. Hence, the function is neither one-one nor onto.

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