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📐 Mathematics  ·  Relations and Functions  ·  JEE

If f(x) = (x + 1)/(x - 1) and g(x) = (x + 3)/(x - 1), then (fog)(x) =

Answer: (2x+2)/(4).

  • A (x+3)/(x-1)
  • B (2x+2)/(4)
  • C (x+3)/(2)
  • D (2x+2)/(x-1+x-1)

Correct answer: B. (2x+2)/(4)

Explanation: g(x) = (x+3)/(x-1). f(g(x)) = (g(x)+1)/(g(x)-1) = [(x+3)/(x-1)+1] / [(x+3)/(x-1)-1] = [(x+3)+(x-1)] / [(x+3)-(x-1)] = (2x+2)/4.

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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