The normal to the curve at the point crosses the -axis at . What is ?

Answer and explanation

Correct answer: A.

  1. Step 1: at , so the normal has gradient .
  2. Step 2: The normal is . At : .
Answer
.
Why not the others: The tangent (gradient ) would cut the -axis at ; comes from the sign slip ; is the normal's gradient; is the -coordinate of the point; is not on the normal.

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