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Let f: R → R be the function defined by f(x) = 2x – 3 ∀ x ∈ R. write f–1

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प्रश्न

Let f: R → R be the function defined by f(x) = 2x – 3 ∀ x ∈ R. write f–1 

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उत्तर

Given f(x) = 2x – 3 ∀ x ∈ R

Now, Leta, b ∈ R such that

f(a) = f(b)

⇒ 2a – 3 = 2b – 3

⇒ a = b

⇒ f(x) is one – one.

Also, If x, y ∈ R such that

f(x) = y

⇒ 2x – 3 = y

⇒ x = `(y + 3)/2` = (y) ∀ y ∈ R

⇒ f(x) is onto and therefore is bijective implies f(x) has an inverse

Let f–1 denote the inverse of f(x) then

f–1(x) = g(x) 

= `(x + 3)/2` ∀ x ∈ R

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अध्याय 1: Relations And Functions - Exercise [पृष्ठ ११]

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एनसीईआरटी एक्झांप्लर Mathematics Exemplar [English] Class 12
अध्याय 1 Relations And Functions
Exercise | Q 4 | पृष्ठ ११

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