If a curve is given parametrically by and , what is the value of at ?

Answer and explanation

Correct answer: B.

  1. Step 1: Differentiate and with respect to : and .
  2. Step 2: Form the derivative: .
  3. Step 3: Substitute : .
Answer
.
Why not the others: evaluates at ; assumes the derivative of constant is ; makes a sign error in the denominator derivative.

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