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Let f: R → R be defined by f(x) = 3x 2 – 5 and g: R → R by g(x) = xx2+1 Then gof is ______

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प्रश्न

Let f: R → R be defined by f(x) = 3x 2 – 5 and g: R → R by g(x) = `x/(x^2 + 1)` Then gof is ______.

विकल्प

  • `(3x^2 - 5)/(9x^4 - 30x^2 + 26)`

  • `(3x^2 - 5)/(9x^4 - 6x^2 + 26)`

  • `(3x^2)/(x^4 + 2x^2 - 4)`

  • `(3x^2)/(9x^4 + 30x^2 - 2`

MCQ
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उत्तर

Let f: R → R be defined by f(x) = 3x 2 – 5 and g: R → R by g(x) = `x/(x^2 + 1)` Then gof is `(3x^2 - 5)/(9x^4 - 30x^2 + 26)`.

Explanation:

Given that, f(x) = 3x2 – 5 and g(x) = `x/(x^2 + 1)`

gof(x) = g(f(x))

= g(3x2 – 5)

= `(3x^2 - 5)/((3x^2 - 5)^2 + 1)`

= `(3x^2 - 5)/(9x^4 - 30x^2 + 25 + 1)`

= `(3x^2 - 5)/(9x^4 - 30x^2 + 26)`

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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 38 | पृष्ठ १५

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