Tuesday, July 22, 2008

6:24 PM: Lisa Smith has entered the room.
6:51 PM: John Beck(Ins) has entered the room.
6:51 PM: John Beck(Ins): Hi, Lisa!
6:52 PM: Stephanie Booker has entered the room.
6:52 PM: John Beck(Ins): Hi, Steph!
6:52 PM: Stephanie Booker: Hi Bill
6:53 PM: John Beck(Ins): How are things back in Baltimore?
6:54 PM: Lisa Smith: Hi!
6:54 PM: Stephanie Booker: Fine
6:54 PM: Lisa Smith: I made it this evening.
6:54 PM: John Beck(Ins): Good, Lisa.
6:55 PM: John Beck(Ins): I'm teaching from Phoenix, AZ tonight so if I sound far away, it's because I'm far away.
6:56 PM: Stephanie Booker: Lol
6:56 PM: Lisa Smith: How is it there? I've never been
6:56 PM: John Beck(Ins): HOT!!!!
6:56 PM: Lisa Smith: Hot?
6:56 PM: Lisa Smith: LoL
6:56 PM: John Beck(Ins): 105
6:56 PM: Lisa Smith: Whoa
6:56 PM: Stephanie Booker: Hot
6:56 PM: John Beck(Ins): And that's in the living room with the AC running full blast.
6:57 PM: Stephanie Booker: Wow
6:57 PM: Lisa Smith: I would be miserable
6:57 PM: John Beck(Ins): I exagerate a little bit.
6:57 PM: John Beck(Ins): We don't spend much time outside.
6:57 PM: John Beck(Ins): Run between the car and the store or the school.
6:58 PM: Lisa Smith: Ok
6:59 PM: John Beck(Ins): We'll be home on Sunday evening, so we can put up with the heat for a few more days.
6:59 PM: Lisa Smith: I'm sure it's nice to get a change of scenery nevertheless
6:59 PM: Jennifer Ann Johnson has entered the room.
6:59 PM: John Beck(Ins): I enjoy Phoenix much more in the winter time!
6:59 PM: John Beck(Ins): Hi, Jenn!
7:00 PM: Jennifer Ann Johnson: Good Evening. How is everyone
7:00 PM: Lisa Smith: Fine and you?
7:00 PM: Stephanie Booker: fine
7:00 PM: John Beck(Ins): We have a very short lesson tonight, so let's get started.
7:00 PM: Stephanie Booker: ok
7:00 PM: Jennifer Ann Johnson: Good, thank you
7:00 PM: John Beck(Ins): Let me know when your're on Ch 12 page 1, please.
7:00 PM: Jennifer Ann Johnson: there
7:00 PM: Lisa Smith: Ready
7:00 PM: Stephanie Booker: there
7:01 PM: John Beck(Ins): Go to page 2, please.
7:01 PM: John Beck(Ins): Here's the formula we'll be using this week.
7:01 PM: John Beck(Ins): Let's click on Tools, then Definitions, please.
7:01 PM: Amanda Cook has entered the room.
7:01 PM: John Beck(Ins): In the top right hand corner is the formula for compound interest.
7:02 PM: John Beck(Ins): Hi, Amanda!
7:02 PM: Amanda Cook: hello everyone
7:02 PM: Jennifer Ann Johnson: hello
7:02 PM: John Beck(Ins): Amanda, we are on Ch 12 page 2. We've clicked on Tools, then Definitions.
7:02 PM: Amanda Cook: thank you
7:02 PM: John Beck(Ins): Our formula is A = P(1 + i)^n
7:03 PM: John Beck(Ins): A is the "compound amount" or you might call it the amount in the future.
7:03 PM: John Beck(Ins): P is the "present value" or the amount of money we deposited originally.
7:03 PM: John Beck(Ins): i is the interest rate per period.
7:04 PM: John Beck(Ins): For example, if our interest rate is 12% compounded quarterly (every 3 months), then i = 12/4 = 3%
7:04 PM: John Beck(Ins): If we have 8% compounded semi-annually, then i = .08/2 = .04
7:04 PM: John Beck(Ins): Okay?
7:04 PM: Stephanie Booker: okay
7:04 PM: Lisa Smith: Ok
7:04 PM: Amanda Cook: ok
7:05 PM: Jennifer Ann Johnson: ok
7:05 PM: John Beck(Ins): Lastly, n is the number of periods that our money is on deposit.
7:05 PM: John Beck(Ins): So if we have 4% compounded monthly and we leave it in the account for 5 years, then n = 5 x 12 = 60
7:06 PM: John Beck(Ins): All right, let's click on "Hide 'em"
7:06 PM: John Beck(Ins): On page 2, P is 1500 since that's the amount we originally deposited.
7:06 PM: John Beck(Ins): Go to page 3, please.
7:07 PM: John Beck(Ins): The interest is compounded semiannually, so i = .04/2 = .02
7:07 PM: John Beck(Ins): Go to page 4, please.
7:07 PM: John Beck(Ins): We leave the money in the account for 3 years, and it is compounded semiannually, so n = 3 x 2 = 6
7:08 PM: John Beck(Ins): Go to page 5, please.
7:08 PM: John Beck(Ins): It's a matter of plugging the values for the variables.
7:08 PM: John Beck(Ins): Go to page 6, please.
7:08 PM: John Beck(Ins): You will need a pocket calculator for this test!!
7:09 PM: John Beck(Ins): Please click on Tools, then Calculator.
7:09 PM: John Beck(Ins): WE
7:09 PM: Lisa Smith: Yes
7:09 PM: Stephanie Booker: okay
7:09 PM: Amanda Cook: we cant use a graphing calculator?
7:09 PM: John Beck(Ins): We need to hit 1.02, then hit the x^y button and finally hit the = button
7:09 PM: John Beck(Ins): Yes, you can use any calculator you are familiar with.
7:10 PM: Amanda Cook: ok
7:10 PM: Meghan Wheeler has entered the room.
7:10 PM: John Beck(Ins): On my calculator I have 1.12616241926
7:10 PM: John Beck(Ins): Hi, Meghan!
7:10 PM: Meghan Wheeler: hello
7:11 PM: John Beck(Ins): Meghan, we are on Ch 12 page 6.
7:11 PM: Meghan Wheeler: thanks
7:11 PM: John Beck(Ins): Did the rest of you get a similar answer for 1.02)^6?
7:11 PM: Lisa Smith: Yes, the same one
7:11 PM: Jennifer Ann Johnson: yes
7:11 PM: John Beck(Ins): GREAT
7:11 PM: Amanda Cook: yes
7:12 PM: Stephanie Booker: yes
7:12 PM: John Beck(Ins): Go to page 7, please.
7:12 PM: John Beck(Ins): I've rounded my final answer to 2-decimal places. We're talking about money so it's natural to round off to 2-decimal places for the final answer.
7:12 PM: John Beck(Ins): Go to page 8, please.
7:13 PM: John Beck(Ins): Let's click on Tools, then Definitions again, please.
7:13 PM: John Beck(Ins): In the to left hand corner is the formula for simple interest.
7:14 PM: John Beck(Ins): We'll use A = P(1 + rt)
7:14 PM: John Beck(Ins): A is the amount in the future.
7:14 PM: John Beck(Ins): P is the amount of our original deposit.
7:14 PM: John Beck(Ins): r is the interest rate
7:14 PM: John Beck(Ins): And t is time measured in years.
7:14 PM: John Beck(Ins): So if you leave the money in the account for 1 year and 6 months, t = 1.5
7:14 PM: John Beck(Ins): Okay?
7:14 PM: Stephanie Booker: okay
7:15 PM: Jennifer Ann Johnson: ok
7:15 PM: Lisa Smith: Ok
7:15 PM: John Beck(Ins): Let's click on "Hide 'em" please.
7:15 PM: John Beck(Ins): Go to page 9, please.
7:15 PM: John Beck(Ins): Go to page 10 please.
7:15 PM: Amanda Cook: ok
7:15 PM: John Beck(Ins): Go to page 11, please.
7:16 PM: John Beck(Ins): Hmmm. It's tough to read that bottom number.
7:16 PM: John Beck(Ins): It is $1,680
7:16 PM: Lisa Smith: Ok
7:16 PM: John Beck(Ins): Go to page 12, please.
7:17 PM: John Beck(Ins): Go to page 13, please.
7:17 PM: John Beck(Ins): Go to page 14, please.
7:17 PM: John Beck(Ins): 9% compounded monthly gives us .09/12 per month.
7:17 PM: John Beck(Ins): Go to page 15, please.
7:18 PM: John Beck(Ins): n is 8 months. That's how long we left the money in the account.
7:18 PM: John Beck(Ins): Go to page 16, please.
7:18 PM: John Beck(Ins): Plug and chug
7:18 PM: John Beck(Ins): Go to page 17, plase.
7:18 PM: John Beck(Ins): please.
7:18 PM: John Beck(Ins): 1.0075^8 = 1.0615988
7:19 PM: John Beck(Ins): Okay?
7:19 PM: Lisa Smith: Ok
7:19 PM: Jennifer Ann Johnson: ok
7:19 PM: Meghan Wheeler: okay
7:19 PM: Amanda Cook: ok
7:19 PM: Stephanie Booker: okay
7:19 PM: John Beck(Ins): Go to page 18, please.
7:19 PM: John Beck(Ins): Go to page 19, please.
7:20 PM: John Beck(Ins): This time we know the amount in the future but we don't know the amount, P, to deposit to reach that goal.
7:20 PM: John Beck(Ins): Go to page 20, please.
7:20 PM: John Beck(Ins): Go to page 21, please.
7:21 PM: John Beck(Ins): Now that we've substituted for the variables, it's a matter of solving for the unknown, P.
7:21 PM: John Beck(Ins): Go to page 22, please.
7:21 PM: John Beck(Ins): 1.02^12 = 1.2682418
7:21 PM: John Beck(Ins): Now we need to solve for the variable, P.
7:21 PM: John Beck(Ins): In other words, we need to divide by the coefficient of P.
7:22 PM: John Beck(Ins): Go to page 23, please.
7:22 PM: John Beck(Ins): You can't see it, but I divided P(12682418) by 1.2682418
7:22 PM: John Beck(Ins): That left me with P
7:22 PM: John Beck(Ins): Go to page 24, please.
7:23 PM: John Beck(Ins): Go to page 25,please.
7:23 PM: John Beck(Ins): This type problem will take a little practice, Class. You might even want to go back and review some algebra.
7:23 PM: John Beck(Ins): Go to page 26, please.
7:24 PM: John Beck(Ins): I've substituted 10,000 for A
7:24 PM: John Beck(Ins): I've substituted 5,000 for P
7:24 PM: John Beck(Ins): Notice that A is twice as big as P.
7:24 PM: Jennifer Ann Johnson: why?
7:24 PM: John Beck(Ins): We want to know how long it takes for our money to double.
7:25 PM: Jennifer Ann Johnson: oh
7:25 PM: John Beck(Ins): I've substituted .005 for i since .06/12 = .005
7:25 PM: John Beck(Ins): Notice that we don't know the value for n
7:25 PM: John Beck(Ins): Pay close attention now.
7:25 PM: John Beck(Ins): Go to page 27, please.
7:26 PM: John Beck(Ins): I've divided 10,000 by 5,000
7:26 PM: John Beck(Ins): And you can't see it but I divided 5,000(1.005)^n by 5,000 also
7:26 PM: John Beck(Ins): I know I've done that since I know 5,000 divided by 5,000 is 1.
7:27 PM: Lisa Smith: Ok
7:27 PM: John Beck(Ins): And the coefficient of (1.005)^n is 1
7:27 PM: John Beck(Ins): Go to page 28, please.
7:27 PM: John Beck(Ins): 10,000 divided by 5,000 is 2
7:27 PM: John Beck(Ins): Remember, we were talking about doubling our money.
7:28 PM: Lisa Smith: Yes
7:28 PM: John Beck(Ins): Now I need to find a tool that allows me to solve for n
7:28 PM: John Beck(Ins): How many of you remember using logarithms?
7:28 PM: Jennifer Ann Johnson: Arghhhh
7:28 PM: Amanda Cook: i hate them!!!
7:28 PM: Lisa Smith: Vaguely
7:28 PM: Lisa Smith: =/
7:28 PM: John Beck(Ins): Hmmm
7:28 PM: Meghan Wheeler: not really
7:28 PM: Stephanie Booker: a lilttle
7:28 PM: John Beck(Ins): You might be the lucky one, Meghan.
7:28 PM: Amanda Cook: does that hhmmm mean that we jsut wont do this part ? : )
7:29 PM: Lisa Smith: LoL
7:29 PM: John Beck(Ins): Hmmmm. I think we'll go ahead and do this part.
7:29 PM: Amanda Cook: oh ok then lol
7:29 PM: John Beck(Ins): Go to page 29, please.
7:29 PM: Stephanie Booker: Lol
7:29 PM: Lisa Smith: Good try Amanda
7:29 PM: Amanda Cook: yeah, it was worth it
7:29 PM: Jennifer Ann Johnson: Can we take a vote?
7:29 PM: John Beck(Ins): Let's click on Tools, then Definitions, please.
7:29 PM: John Beck(Ins): Yes, but I get 50 votes.
7:30 PM: Lisa Smith: LoL
7:30 PM: Jennifer Ann Johnson: boooo
7:30 PM: John Beck(Ins): Dictatorship!
7:30 PM: Amanda Cook: lol
7:30 PM: John Beck(Ins): But I'm a benevolent dictator.
7:30 PM: John Beck(Ins): At the bottom of the page is a line that says the log of a number raised to a power is equal the that power times the log of the number.
7:31 PM: John Beck(Ins): Log x^n = n Log x
7:31 PM: John Beck(Ins): Okay?
7:31 PM: Lisa Smith: Ok
7:31 PM: Jennifer Ann Johnson: sure
7:31 PM: Amanda Cook: ok
7:31 PM: Meghan Wheeler: yes
7:31 PM: John Beck(Ins): That's the trick we need to use when we solve for a variable that is an exponent.
7:32 PM: Amanda Cook: the a is the variable?
7:32 PM: John Beck(Ins): Click on "hide 'em" Please.
7:32 PM: John Beck(Ins): It is the base of the log, Amanda. This semester we'll use base 10. That is usually referred to as "common logarithms."
7:33 PM: Amanda Cook: ok so then its always 10 right now?
7:33 PM: John Beck(Ins): Go to page 29, please.
7:33 PM: Amanda Cook: oh ok ig ot it
7:33 PM: John Beck(Ins): If you are using a scientific calculator, you might see log which means base 10.
7:33 PM: John Beck(Ins): But you might also see ln which means log to the base e.
7:33 PM: John Beck(Ins): We'll stick to common logs.
7:33 PM: John Beck(Ins): Base 10
7:34 PM: Lisa Smith: Ok
7:34 PM: John Beck(Ins): On page 29, I've taken the log of 2 and I've taken the log of 1.005^n
7:34 PM: John Beck(Ins): Go to page 30, please.
7:34 PM: John Beck(Ins): To the right of the equal sign, we see that I now have n times the log of 1.005
7:35 PM: John Beck(Ins): To the left of the equal sign, I still have log 2
7:35 PM: John Beck(Ins): Go to page 31, please.
7:35 PM: John Beck(Ins): Let's click on Tools, then calculator, please.
7:35 PM: John Beck(Ins): Click on 2, then on log, and then on the equal sign.
7:36 PM: John Beck(Ins): Did you get .30102999566?
7:36 PM: Lisa Smith: Yes
7:36 PM: Meghan Wheeler: yes
7:36 PM: Jennifer Ann Johnson: yes
7:36 PM: Stephanie Booker: oyes
7:36 PM: John Beck(Ins): Don't forget to get familiar with your pocket calculator before you come to take the test!!
7:36 PM: John Beck(Ins): Go to page 32, please.
7:36 PM: Amanda Cook: yea
7:37 PM: Amanda Cook: sorry took me a little longer
7:37 PM: John Beck(Ins): I'm solving for n, so I've divided by the coefficient of n which is .0022
7:37 PM: John Beck(Ins): No problem, Amanda.
7:37 PM: John Beck(Ins): Go to page 33, please.
7:37 PM: John Beck(Ins): I've rouned off to 1-decimal place.
7:38 PM: John Beck(Ins): Since we started talking about compounding monthly, I know that my unit of measure is "Months."
7:38 PM: John Beck(Ins): Go to page 34, please.
7:38 PM: John Beck(Ins): At the end of 136 months our money wouldn't have quite doubled, so we round up to 137 months.
7:39 PM: John Beck(Ins): Make sense?
7:39 PM: Lisa Smith: Yes
7:39 PM: Amanda Cook: yes
7:39 PM: Jennifer Ann Johnson: yes
7:39 PM: Meghan Wheeler: yes
7:39 PM: Stephanie Booker: yes
7:39 PM: John Beck(Ins): Had my original problem stated "compounded quarterly" I'd be talking about 3-month periods.
7:40 PM: John Beck(Ins): So Logs weren't that painful, were they?
7:40 PM: Jennifer Ann Johnson: Not too bad
7:40 PM: Lisa Smith: I guess not
7:40 PM: Stephanie Booker: no
7:40 PM: John Beck(Ins): But you do need to practice this type problem!
7:40 PM: Amanda Cook: nah
7:40 PM: John Beck(Ins): Okay, Class, that's it for tonight.
7:40 PM: Stephanie Booker: ok
7:40 PM: Amanda Cook: not YET
7:40 PM: John Beck(Ins): Any questions?
7:40 PM: Amanda Cook: no
7:40 PM: Stephanie Booker: no
7:41 PM: Jennifer Ann Johnson: Have a good night
7:41 PM: Meghan Wheeler: none
7:41 PM: Jennifer Ann Johnson has left the room.
7:41 PM: Lisa Smith: no...have a safe flight back
7:41 PM: John Beck(Ins): G"night, Jenn
7:41 PM: Lisa Smith: night
7:41 PM: John Beck(Ins): Thanks, Lisa.
7:41 PM: John Beck(Ins): G'night, Lisa.
7:41 PM: Amanda Cook has left the room.
7:41 PM: Lisa Smith has left the room.
7:41 PM: Stephanie Booker: GN!
7:41 PM: Meghan Wheeler has left the room.
7:41 PM: John Beck(Ins) has left the room.
7:41 PM: Stephanie Booker has left the room.