Applications of derivatives

Practice sheet

Fresh questions from the whole chapter, to do on paper.

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  1. Find lim⁡x→0e5x−1x\displaystyle\lim_{x \to 0} \dfrac{e^{ 5x} - 1}{x}.
  2. Find lim⁡x→01−cos⁡(6x)x2\displaystyle\lim_{x \to 0} \dfrac{1 - \cos(6x)}{x^2}.
  3. Find lim⁡x→1x7−1ln⁡x\displaystyle\lim_{x \to 1} \dfrac{x^{ 7 } - 1}{\ln x}.
  4. f(x)=x3−12xf(x) = x^3 - 12x. At which xx does ff have a local maximum?
  5. Here is the graph of the derivative y=f′(x)y = f'(x). Tap the point of this graph at the xx-value where ff has a local maximum.
  6. f(x)=x3−3x2f(x) = x^3 - 3x^2. At which xx does ff have an inflection point?
  7. f′(8)=0f'(8) = 0 and f′′(8)=3f''(8) = 3. What happens at x=8x = 8?
    1. A local minimum
    2. A local maximum
    3. An inflection point
  8. f′(1)=0f'(1) = 0 and f′′(1)=0f''(1) = 0. What can you conclude about x=1x = 1?
    1. Nothing yet: it could be a maximum, a minimum or neither
    2. It is an inflection point
    3. It is a local maximum
  9. Find the maximum value of f(x)=x2−6xf(x) = x^2 - 6x on [0,8][0, 8].
  10. Find the minimum value of f(x)=x3−3xf(x) = x^3 - 3x on [0,2][0, 2].
  11. f(x)=x2f(x) = x^2 on [2,5][2, 5]. Find the cc given by the Mean Value Theorem.
  12. f(x)=x3f(x) = x^3 on [0,4][0, 4]. Find the cc in (0,4)(0, 4) given by the Mean Value Theorem.