The function f: x \(\to \sqrt{4 - 2x}\) is defined on the set of real numbers R. Find the domain of f.

  • A \(x<2\)
  • B \(x \leq 2\)
  • C \(x = 2\)
  • D \(x > -2\)
waec 2017furthermathematics

The correct answer is B. \(x \leq 2\)

\(f : x \to \sqrt{4 -2x}\) defined on the set of real numbers, R, which has range from \((-\infty, \infty)\) but because of the root sign, it is defined from \([0, \infty)\). 

This is because the root of numbers only has real number values from 0 and upwards.

\(\sqrt{4-2x} \geq 0 \implies 4-2x \geq 0\)

\(-2x \geq -4; x \leq 2\)

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