Brandon Notices

I was at Walgreens yesterday, looking for a new portable FM radio. Instead, I bought a calculator.



The TI-30XS Multiview Calculator, normally about $22, was on sale at $15, and it looked cool, so I got it. It has a neat feature called MathPrint mode, where it displays mathematical expressions in a more natural way (like how you write math on paper) rather than relying on a bunch of parentheses and junk.



On the left above, you can see a particularly complicated and useless expression as it would have to be typed on the TI-84 Plus Silver Edition. It has a lot of parentheses, and it's kinda hard to see what's going on. On the right is how the expression looks on the TI-30XS Multiview Calculator, with the MathPrint mode on. It's obviously a lot easier to see what's going on. (MathPrint can be turned off so that expressions can be typed in the classic mode.)

The TI-30XS also automatically simplifies fractions and roots. The first picture in this post has two examples of it doing this. On a different calculator, the answers would instead be displayed as decimals. There's a button you can simply press on the TI-30XS to convert these fractions or roots to decimals and vice-versa. It seems to be called the answer toggle button, and the button looks like this ◄ ►. There are two ways to input division: as a stacked fraction, or simply using the ÷ sign. The stacked fraction will try to give another fraction as an answer; the ÷ sign will yield a decimal answer.

  

You can see in the picture above that the calculator is also pretty smart with trigonometry. The TI-30X IIS on the left above calculated the sine of π as an ugly decimal. The TI-30XS is smarter than that, though. It displays the answer in exact terms using a fraction and a root, as it should. By pressing the answer toggle button, this can quickly be converted to a decimal, too.

So the TI-30XS seems to be able to do everything the TI-30X IIS can do, but there are still a few gripes I have with it. The answer toggle button is right above Enter (=), which is where plus usually is on TI calculators—the +, -, ×, and ÷ buttons are all moved one button up on the calculator, which takes a little getting used to. I keep pressing the answer toggle button when I mean to press plus.

Another issue is that there doesn't seem to be a way to wrap fractions or roots around expressions you have typed already. For a simple example, say you've typed 4, but then you realize you need to take the square root of 4. On the TI-30X IIS or the TI-84, you could move the cursor back in front of the 4 and insert a square root symbol. If you try to do that on the TI-30XS, though, it'll put a square root radical to the left of the 4, but there'll be a blank inside the radical, waiting for you to type in a number to go under it. The 4 will be to the right of the root, implying multiplication. I suppose you could work around this by raising 4 to the 1/2 power, but that seems imperfect.

Overall, it's a snazzy little calculator with a bunch more features I didn't even mention. The colors are bold and modern looking, but one of my friends said it looks like a child's toy. It's pretty thin (even more so without the cover slide case) and fits comfortably in the hands, and the buttons repsond well. (I think the TI-30X IIS is a bit too narrow to hold comfortably, and if you try to press a button before releasing the previous button, it'll ignore the second button press.) I would recommend to anyone looking for a cool calculator.

I was at Safeway this evening, looking at the huge variety of toothpaste products, trying to choose which one to buy. I was looking at the price tags, and noticed something very irritating.


This Crest Whitening Plus Scope Toothpaste has a red sale tag, and it says that the box of toothpaste costs $2.99. It also displays the toothpaste's unit price: 37.4¢ per ounce.


This Colgate Total Advanced Whitening Toothpaste also has a red sale tag, and it is the same price, at $2.99. The unit price is displayed on this price tag too: $8.26 per pound.

Wait! Why does Safeway give the unit price for the Crest in cents per ounce, but gives it for Colgate in dollars per pound? These are not compatible!

It should be that I could look at the price tags for both the Crest and the Colgate and be able to compare them very easily. But I can't do that, because the units are incompatible! I would have to pull out my calculator and multiply the per-ounce price by 16 to compare them. (Incidentally, the Crest toothpaste contains 8 ounces of toothpaste, whereas the Colgate has 5.8 ounces, so you get more toothpaste per dollar with the Crest.)

AUGH! I shouldn't have to do this! I thought the point was to give customers the opportunity to quickly compare the price per amount of something without having to whip out the calculators!


This last example makes the whole situation even worse. This 6-ounce Colgate Max Fresh Toothpaste has a red tag price of $2.49. Unit price: $41.50 per 100. Per hundred of what? From what I can tell by shaking the box, there seems to be only one tube of toothpaste in it. If I bought 100 of these boxes, that would cost $249.00, not $41.50. I thought about this a moment and did some calculations to check: Safeway means that this toothpaste costs $41.50 per 100 ounces! Why??

Safeway, you're driving me crazy!

I'm taking Math 300, where we deal with all sorts of math reasoning, proofs, and logic. I got back one of my homework problems. The question was this:

A certain island is inhabited by two tribes of people. The members of one tribe always make true statements, and the members of the other tribe always make false ones. (And they are all skillful logicians.) The natives all know who is a truth-teller and who is a liar, but a visitor cannot tell the truth-tellers from the liars just by looking at them. . . . Suppose you meet three natives — A, B, and C — and the first two make the following statements:

A: B is a liar.
B: If A is a liar, then so is C.

Using only this information, figure out whether A, B, and C are truth-tellers or liars, and explain your reasoning.

And I made a rather careless mistake, right at the end:



Ack! I lost one point out of ten for this...

Today was Math Day. It was a field trip to the University of Washington. Before it all got started, we were all seated in a huge auditorium in Meany Hall. Aaron and I thought about what presentations to view later, and we thought that Hyperbolic Geometry would be fun, and so would Aeronautics and Astronautics. However, A&A required a "ticket", and neither Mr. Worster nor any of the other teachers had tickets for that. So instead, Mr. Worster gave us two tickets to Applied Physics, and said to try to trade those for tickets to Aeronautics and Astronautics.

Everybody had to watch the plenary presentation, whether they wanted to or not. Everyone was gathered in the auditorium in Meany Hall to watch some guy give a presentation about securely transferring data (like credit card numbers, etc.) over the Internet. I thought it was pretty interesting, but word is that a lot of people found it to be "boring" and "stupid". Ah well, I guess not everything can please everybody.

So afterwards, Aaron and I went to the ticket trading booth, where people set down tickets they wanted in exchange for tickets they didn't want. Aaron, who is much taller than me, could see that there were no A&A tickets there. One guy had one A&A ticket, and didn't want it, but refused to give it to us because he wanted it to exchange for something better.

We went to the hyperbolic geometry presentation, which was actually called Images of Hyperbolic Geometry. Aaron was disappointed that he only skimmed the surface of hyperbolas, mostly only showing pictures. He also complained that the idiot had no idea what he was talking about, but to be fair, he wasn't a professor, despite the fact that I kept calling him "the professor" (it wasn't until later that I found out he wasn't one). But still, to be fair, the pictures were interesting and neat!

Since we couldn't get tickets to A&A, we went to Trial by Mathematics, which didn't require a ticket (the presentations didn't require tickets, only the "field trips" and hands-on things). It was interesting because she mentioned that most people only identify other people by their hair and eyes, the most common things mentioned were higher on the body. She discussed how math has been used in several trials, many of them using probability ("it's a 1 in 12 million chance this couple did it...").

Lunch was next, and since it was an hour, we went and played with those little logic thinking sliding puzzle things that you see in gift and puzzle stores and such. Then we all boarded the buses, and one girl was missing. But they found her and we left.

My favorite part was that the auditorium was called Meany Hall.

The school was nearly empty today.

The girls' basketball team went to state competitions far, far away, and most of the student body went with them, just to watch. So everybody else stayed at school. I was one of those people.

Right before English class, everybody boarded the rooter buses. So English class, typically, was pretty empty. There were only like 10 out of 30 or so people in class. However, Ms. Hudemann refused to let this ruin her class. We continued watching The Great Gatzby, and the rest of the class will just have to rent the movie if they want to catch up.

ASL was a lot more fun. There were only like 7 out of 26-ish people there. Most of us were over on the same side of the classroom, so it was cool to have the other side of the class practically empty. First we had a practice test, and I did pretty well (except I wrote down 25 when she signed 15). Ms. Brinkley had nothing else planned—we could choose to watch a movie or read for over an hour, and knowing the movies she chooses, we chose to read. However, it didn't take long for us to stop reading and just start doing other stuff. I played dots 'n' curves on the board with Rachel, Alex, and Steve.

Lunch was pretty normal, but Calculus was way off! Out of our class of 18-ish, there were only 5 of us, excluding Conner, who was taking a test outside of the classroom. We watched a video about integrals that Mr. Worster thought would be fun to watch, but it really wasn't very good—he wanted to test it on us to see how fun it was, I guess. It wasn't. I waved the tissue in the air like a surrender flag, and he laughed at that and stopped the movie. Then we went over the test. I didn't do too well on it... I asked about one problem and I entered the equation incorrectly into my calculator but Mr. Worster reawarded me with those points because it was a strange mistake involving the way the calculator handles complicated exponents, but I got the math totally correct.

The girls' basketball team lost today—that means that they play tomorrow morning at 9:00 AM. Which means that I bet a bunch of the school will go to that game too. If the "Lady Mavs" had won, they would have played tomorrow at 3:30 PM, and students would not be able to miss school tomorrow. I bet a lot of people are happy that they lost the game.

Last Friday, I missed a test in Calculus test because I went to Kansas (remember?) so Mr. Worster was nice about it and let me make it up on Monday. And guess what. I got 100% on it! Phew, I thought I wasn't going to do so well. Derivatives are a little tricky.

Then, on Tuesday, I took a test in History about the Civil War. Blech... history. I'm not good at history. Then, we took our final early in Walking class. Phew... I was tired after that. We walked down the back road to the Meadowdale Beach, then walked up the Meadowdale Beach Trail, and back to school. It was about 4.5 miles, and when it wasn't uphill, it was steep downhill with slippery leaves.

Tuesday night, I made two dozen no-bake cookies for Christmas presents for my friends. Steffi helped me wrap them, and I gave them to some of the friends I saw yesterday and earlier today. I also made some math-themed badges for Mr. Worster. He really seemed to like them. He wore three of them during class. Audrey liked them, and asked where he got them. He said, "Well, um, Brandon gave them to me!" I'll post some of the images for the badges I made:

 

The first one simplifies to i/8 ("I overate"). You need to know trigonometry to find the fourth one funny.

In pre-calculus class today, class was kinda boring. Mr. Youngren was yabbering about hyperbolas. He talked about some kind of ellipse on the graph, and he said that you have to circumscribe the ellipse. A girl in class giggled and said, "circumcise." Everybody laughed. Mr. Youngren turned toward her and said, "Careful, Jenny. It's 'circumscribe.' " He then turned back to the board, lifted his marker to the ellipse, and continued, "so you circumcise the circle—" and sputtered, and everybody laughed. Even Mr. Youngren. Which just goes to show you that everybody can laugh at his or her own mistake. After that, it was just boring again.