Day 39: Heart of Mathematics

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Announcements:
- Fractal/Tree homework returned (graded #21 and #32):
  - #21: each segment should be the same length, at each level. Have a look at "Stairs" at this site.
  - #32: one way to think of constructing these is by addition, rather than by subtraction.
  - nice work!
- Your show-n-tell item will ideally be something that you see in the world that reflects our course: it shouldn't be necessary to "make something up". Look around you!
- Last time we randomly chose our presentation dates
- Reminder: Homework for the financial unit is: pp. 678-681, #1, 3, 4, 9, 10, 12; Type up #20. Due Monday, 12/8 (note change in due date).
More Financial Math (Section 8.3: Money Matters)
- I see on CNN that the best web site for personal finance is Mint.com.
  I found this nice Visual Guide to the Financial Crisis on the site.
- How do the credit card companies make so much money? (compounding interest!)
  - Pretty straight forward: #6, p. 678
  - Here's a twist: #11, p. 679
- How do mortgages work?
  - Other loans can be calculated the same way: for example, CitiFinancial's loan shark fishing attempt on me.
  - Here's another straight-forward mortgage problem: #16, p. 680
- A "real-world" example: do you use those balance-transfer checks? I got this offer awhile back.
  - What are the hidden costs (buried in the fine print)?
  - What would $1000 cost me for a year, if I take it out May 1, and pay nothing back? (By the way, the balance transfer APR is 18.99%).
- Inflation: how to convert dollars to a common standard.
  - Inflation calculator
  - Historical Consumer Price Index table (from 1913)

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