For which values of does the line meet the circle at two distinct points?

Answer and explanation

Correct answer: D.

  1. Step 1: Substitute: gives .
  2. Step 2: Two distinct points need a positive discriminant: , so and , i.e. .
Answer
.
Why not the others: or is where the line misses the circle; uses ; includes large where the line misses; uses .

Practise more Conditions on a parameter.

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