SECTION

MEMORIZE AND KNOW HOW TO USE!

(PS: YOU ARE ALLOWED A 3x5 CARD)

PROBLEMS

4A

Know how to prorate.

Exercises – 37, 39

Quiz

4B

Know difference between simple and compound interest. And be able to compute both (see example 3).

A = P(1+APR%/n)(nY)

APY = (Absolute One Year Increase)/(Starting principal)

Continuous Compounding A = PeY·APR

Example - 3

Exercises - 49, 51, 53, 57, 61, 63, 65, 73, 77

Quiz

4C

Total Return = (A-P)/P

Annual Return = (A/P)(1/Y)-1

Savings Plan Formula -

A = PMT((1+APR%/n)(nY)-1)/(APR%/n)

Know about Stocks and Bonds (See example 7, 8, 10)

Examples – 7, 8, 10

Exercises – 45, 49, 53, 55, 61, 65

4D

Loan Payment Formula -

PMT = P(APR%/n)/(1-(1+APR%/n)(-nY))

Mortgages and Closing Costs

Exercises – 25, 31, 37, 39, 49, 51, 53

8A

Know when growth is linear and when exponential. Be able to sketch a graph illustrating both.

Understand parable 1, 2, 3

Example - 1

Exercises – 19, 21, 27, 31, 35, 40

8B

Be able to graph exponential and linear decay

Approximate Thalf ≈ 70/P

Approximate Tdouble ≈ 70/P

Q = Q0(2)(t/Tdouble) (For exponential growth)

Q = Q0(2)(-t/Thalf) (For exponential decay)

Thalf = -log10(2)/log10(1+r)

Tdouble = log10(2)/log10(1+r)

(Remember it doesn't matter what base you use for log as long as it's the same top and bottom)

Know when approximate can be used

Study the log review on page 531

Be able to solve for variables in exponents

Be able to figure out half life and/or doubling time given a graph.

Understand the Carbon-14 example worked out in class

Examples – 5, 8, 9

Exercises – 35, 39, 47, 49, 55, 57, 59, 61, 63, 65

8C

Logistic Growth Rate = r(1-P/C)

Know about carrying capacity, overshoot, collapse and how logistic growth compares with exponential. Figure 8.4

Growth Rate = Birth Rate – Death Rate

Example – 1, 2, 3

Exercises – 23, 25, 27, 29, 35

9C

Q = Q0(1+r)t

Know what the exponential function looks like – Figure 9.17 – and understand it's sensitivity to growth rate.

Be able to use the exponential function in all three forms.

Understand Examples 2, 3, 4, 6

Examples - 2, 3, 4, 6

Exercises – 37, 39, 49, 51, 53



QUIZ SOLUTIONS

[10 points] I) What is the annual interest payment if you maintain an average balance of $650 on your credit card
 with 18% annual interest rate? 

                     0.18*$650 = $117

[10 points] II) If Sarah pays $4500 twice for tuition and fees for Fall and Spring Semesters and $1500 for Summer,
 prorate these expenses to find how much it costs every month for Sarah to attend school?

                     $(2*4500 + 1500)/12months = $875/month

[10 points] III) You take a short term loan of $3600 for 3 months at 12% APR compounded monthly. What is the interest
 you have to pay on this loan at the end of three months? If the interest was compounded continuously, would the 
interest be less or more? (Hint: Interest is A-P)

                      remember n = 12 and Y = 3/12 years,
                     so interest is $3600*(1+12/(12*100))^(12*3/12) – $3600 = $109.08