Test 1 Topics

Difference equation material can be found in sections 10.1-10.4 of the supplemental text. You can find the supplemental text in the resources section of WebAssign, but I am also posting it here: ma_131_supplement

You should be able to:

  • Write the difference equation for a word problem (applications in both finance and population growth). Sec. 10.1
  • Write the general solution. (Don't forget about the special situation when .) Sec. 10.2
  • Sketch the graph of various difference equations. Sec. 10.3
  • Describe the long term behavior and vertical direction of the graph of a difference equation. Sec. 10.3
    • Sketch the graph of a function that is:
      • monotonic, oscillating, increasing, decreasing, constant, unbounded, bounded (asymptotic to a line).
    • Sketch the graph of a function that is neither monotonic, oscillating, nor constant.
  • Solve a word problem by using the graph of the difference equation (see for example example 10 on page 400 of the supplemental text). Sec. 10.3
    • Practice problem 3 may also be helpful (its solution is given after the homework problems). For the this type of problem, I would like you to include three graphs on your test.
  • Solve a word problem using the general solution. Sec. 10.4
    • You may be asked to solve for an initial deposit or loan amount; or a monthly withdrawal, payment or deposit amount.

You are also responsible for Sections 1.1-1.4 (pages 86-87 on the limit definition of the derivative) from the text book.

You should be able to

  • Graph a linear equation and give its slope. Sec 1.1
  • You should be able to use the power rule to compute the derivative of function at a point or as a function. Sec 1.2
  • You should be able to give the slope of the tangent line for a function at a point either using the power rule or the graph of and . See for example, Quiz 2. Sec 1.3 
  • You should be able to sketch the graph of a tangent line (as we did for ).
  • You should be able to use the limit definition of the derivative to compute the derivative of a function at a point . See for example Example 7 from Section 1.3 and Examples 5-7 from Section 1.4. Sec 1.3-1.4 
    • I will provide the equation for this limit .

Difference equations practice problems

Below you'll find a copy of the difference equation practice problems from last Wednesday, plus a copy of the solution.

Solutions: Difference equation practice problems

Worksheet: practice problems

In numbers 3b, remember that the biggest possible withdrawal happens when Gary takes out all of the interest he earns each month, and that corresponds with the constant graph.