What is the domain of ?

Answer and explanation

Correct answer: A.

  1. Step 1: The radicand must be non-negative: .
  2. Step 2: Solving gives (the inequality flips on dividing by a negative).
Answer
.
Why not the others: : The endpoint was excluded although is defined. : The direction of the inequality is reversed. : The constant was moved with the wrong sign.

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