Math 141.1 - Test I
Tuesday, Sept. 21, 1993

Name  Show your work for full credit

  1. Let f be defined by

    f(x) = ì
    í
    î
    5-x2,
    if   -1 < x < 1
    2(2-x),
    if   x ³ 1.
    1. Sketch the graph of f.
    2. Determine the domain and range of f.
    3. Is f continuous at the points x = -1,0,1? Verify your answer.

  2. Using the properties of limits, find the the following limits putting in each step:
    1. limx® 3 [(x2-4x+3)/(x2-9)]
    2. limx® 2 [(x2-4x+3)/(x2-9)]
    3. limx® 0 [tan(x)/x cos(x)]

  3. Using the definition of derivative and the properties of limits, compute the derivative of f at x = 2 where f is given by
    f(x) = x2+x-3.
  4. Let

    f(x) = 2x3-6x-2.
    1. Compute the slope of the tangent line to the graph of f when x = 1.
    2. Give the equation of the tangent line to the graph of f at the same point.
    3. For which values of x is the tangent line horizontal?

  5. Using the properties of derivatives, determine the derivatives of each of the following functions:
    1. g(x) = (2x2-3)(1-2x+x2)
    2. f(x) = x2 ex -2x3        (Hint: You can use Dx(ex) = ex)
  6. [EXTRA CREDIT]
    Using the definition of `limit', prove that

    lim
    x® 0 
    x2 = 0.


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