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📐 Mathematics  ·  Relations and Functions  ·  JEE

If f(x) = (x - 1)/(x + 1), the value of f(f(x)) is:

Answer: 1-x.

  • A x
  • B 1/x
  • C -1/x
  • D 1-x

Correct answer: D. 1-x

Explanation: f(f(x)) = f((x-1)/(x+1)). Substituting: numerator = (x-1)/(x+1) - 1 = -2/(x+1). Denominator = (x-1)/(x+1)+1 = 2x/(x+1). Result = -1/x.

Concept context

Ordered pairs, Cartesian products, types of relations and functions, domain and range. Foundation for calculus and Class 12 algebra.

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