The Product and Quotient Rules · seed 1 · A4, ink-friendly. The answer key prints on its own page for grown-ups.
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Products and quotients, differentiated

Mathematics · Calculus & Analysis · ages 18-19
Name ______________________   Date ____________
  1. Using radians, let h(x) = x sin x. Find h'(pi/2).

    Answer: ______________

  2. For h(x) = (x+1)(x+2), find h'(1).

    Answer: ______________

  3. For the product 5x, multiplying the derivatives of the factors 5 and x gives its correct derivative.

    Circle one:   True   False

  4. Using radians, what is the derivative of x²sin x?

    • 2x sin x+x²cos x
    • 2x cos x+x²sin x
    • 2x sin x-x²cos x
  5. For h(x) = (2x+3)/(x-1), find h'(2).

    Answer: ______________

  6. For x distinct from 2, h(x) = (x²-4)/(x-2). What is h'(x) on its domain?

    • 1
    • x+2
    • 2x
    • 0
  7. For h(x) = (x+2)/(x+3), find h'(-2).

    Answer: ______________

  8. At a point, differentiable f and g have f = 2, f' = -1, g = 4 and g' = 3. What is the derivative of f/g there?

    • 5/8
    • -5/4
    • 1/8
    • -5/8
  9. Differentiable functions satisfy f(2) = 3, f'(2) = 1, g(2) = 4 and g'(2) = 5. Find (fg)'(2).

    Answer: ______________

  10. Using radians, what is the derivative of x cos x?

    • cos x+x sin x
    • cos x-sin x
    • cos x-x sin x
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Answer key

For grown-ups. Fold this page away before handing over the rest.

Products and quotients, differentiated W1-mt_NJ7INJ0jfv-s1

  1. 1 · The derivative is sin x+x cos x; at pi/2 it equals 1.
  2. 5 · The product derivative is (x+2)+(x+1), giving 5 at 1.
  3. False · The true derivative is 5; multiplying the separate derivatives gives 0.
  4. 2x sin x+x²cos x · The product rule adds 2x sin x and x²cos x.
  5. -5 · The numerator simplifies to -5 and the squared denominator equals 1 at 2.
  6. 1 · On the original domain the quotient equals x+2, whose derivative is 1.
  7. 1 · The quotient derivative is 1/(x+3)², which equals 1 at -2.
  8. -5/8 · The numerator is (-1)4-2(3) = -10 and the denominator is 16.
  9. 19 · The pointwise product rule gives 1(4)+3(5) = 19.
  10. cos x-x sin x · The contributions are cos x and -x sin x.
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