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If f(x) = x-1x+1, then show that f(1x) = – f(x) - Mathematics

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Question

If f(x) = `(x - 1)/(x + 1)`, then show that `f(1/x)` = – f(x)

Sum

Solution

f(x) = `(x - 1)/(x + 1)`

Substituting x by `1/x`, we get

`f(1/x) = (1/x - 1)/(1/x + 1)`

= `((1 - x)/x)/((1 + x)/x)`

= `(1 - x)/(1 + x)`

= `(-(x - 1))/(1 + x)`

= `- (x - 1)/(x + 1)`

Therefore,

We get `f(1/x)` = – f(x)

Hence proved.

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Chapter 2: Relations and Functions - Exercise [Page 30]

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NCERT Exemplar Mathematics [English] Class 11
Chapter 2 Relations and Functions
Exercise | Q 20.(i) | Page 30

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