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Which of the following functions from Z into Z are bijections?

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प्रश्न

Which of the following functions from Z into Z are bijections?

विकल्प

  • f(x) = x3 

  • f(x) = x + 2

  • f(x) = 2x + 1

  • f(x) = x2 + 1

MCQ
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उत्तर

f(x) = x + 2

Explanation:

For bijection on Z, f(x) must be one-one and onto

Function f(x) = x2 + 1 is many-one as f(1) = f(–1)

Range of f(x) = x3 is not Z for x ∈ Z.

Also f(x) = 2x + 1 takes only values of types = 2k + 1 for x = k ∈ Z

But f(x) = x + 2 takes all integral values for x ∈ Z

Hence f(x)= x + 2 is bijection on Z

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अध्याय 1: Relations And Functions - Exercise [पृष्ठ १५]

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एनसीईआरटी एक्झांप्लर Mathematics Exemplar [English] Class 12
अध्याय 1 Relations And Functions
Exercise | Q 39 | पृष्ठ १५

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