Day 20 in Mat129

Today:

• Announcements
  • New assignment:

    Tue

    3/2

    Section 3.9 (examples)

    Read 4.2: Max/Mins

• Today: related rates problems
  • Draw a picture
  • Assign sensible variable names
  • "Relate" the variables (especially rates, i.e. derivatives)
  • Use familiar mathematical elements
    • Chain rule
    • Similar triangles
    • Pythagorean theorem
    • Other geometric relationships (e.g. volume of a cone)
  • Use Units wisely -- they can help you with reality checking, especially. Don't forget them at the end! But you may avoid cluttering up equations with them...

  • Examples:
    • #14: a shadow problem
    • #19: a ladder problem