Which calculator? Hp 50G vs Ti89 Titanium

ugeminorum

Apparently, you have not been taught order of operations. Or, more accurately, you have not been taught what is or is not an operation. There is only one operation in the given expression. That operation is the power operation. The base is negative 2.

You mistake the - sign as an operation. It is actually part of the number itself.

As written, the correct answer is 16. Raising a negative number to an even power ALWAYS results in a positive answer.

You should really get your math correct prior to posting.

George Jones

Negation is an operation; it's an example of a unary operation.

No, according to the standard order of operations, -2^4 = 16.

There is no law that prohibits a company from marketing calculators or computer software (e.g, Microsoft Excel) that use a non-standard order of operations, but I think it is silly to do so.

This reminds me of a joke I once read. How many Microsoft employees does it take to change a burnt-out lightbulb? None. Microsoft declares darkness the standard.

A standard order of operstions aids communication; if everyone follows the standard, then everyone knows what a given expression means. In the standard order of operations, the power operation takes precedence over negation.

As an example, consider the equation

-x^2 + 16 = 0.

According to the standard order of operations, x = -4 and x = 4 are solutions to this equation. According to your non-standard order of operations, x = -4i and x = 4i are solutions to this equation, which seems quite bizarre.

I applaud TI for using the standard order of operations. Maple also follows the standard order of operstions and returns -2^4 = -16.

Agreed.

ugeminorum

So, in the expression -2^4, -2 is not a number. What happened to the negative numbers? If negation is taken purely as an operation, then there are no such things as negative numbers. Whenever I encounter a number with a negative sign, I am to interprut it as a positive number with the negation operation applied? That is the conclusion your logic follows. I, for one, stand by the negative numbers.

In the equation -x^2+16=0, the - is understood to be -1 (- DOES NOT REPRESENT A NEGATION IN YOUR EXAMPLE). Read any elementary high school algebra text. So the equation actually reads -1*x^2+16=0. The solutions are x=4 and -4. This is quite different from -2^4, where -2 is a number. Your answer can only be derived if the expresion is rewritten as -(2^4). There is a big difference. It is not the order of operations you don't understand, it is the actual mathematical notation for which you have no grasp.

It is okay for TI and Maple to handle the expression the way the do, as long as it is documented.

And, for your infomration, I am following the ONLY order of operation.

George Jones

Wow!

Do you really mean to argue that different orders of operations apply to -2^4 and -x^4?! This is what you're doing.

The ultimate number crunching software, Fortran, also returns -2**4 = -16. The unary operation of negation is given the same precedence as the binary operation (subtraction) from which its is derived, i.e., -2**4 is the same as 0 - 2**4.

This is incorrect. There are many, many different orders of operations. We choose one order of operations as a communications aid.

My final argument by authority: I asked my wife, and she says that -2^4 = -16. If you want to start an argument by taking it up with her, good luck!!!

PS My wife has a bachelor's in physics, a master's in physics, and a master's in engineering.

ugeminorum

NO. Do you understand that -x^4, as written, actually stands for -1*x^4. Go look at an actual mathematics book for reference. So, follow the order of operations; take the four power first, then multiply by -1. If you would like, consult ANY standard algebra text. Wikipedia is not an accepted scientific or mathematical reference, the last time I checked. When it is acceptable to quote from Wikipedia in referred papers, I'll reconsider my stand on this.

I don't consider Fortran to be a final arbiter in this matter, as it was designed for engineers. It also doesn't matter what programming language or brand of calculator does what. I am sure that they all account for their operations. Again, okay if defined up front.

Really, I thought we were talking of the only order of operations that is widely accepted among all Mathematicians when one is taling about the RING of real numbers.

Wouldn't want to argue with your boss. However, I actually have a bachelors degree and masters degree in Mathematics, the actual subject being discussed. I think I am qualified to speak on this topic. I don't think physics and engineering majors quite get into the foundations of Mathematics.

Phykick

-2^4=(-2)(-2)(-2)(-2)=

Anyone???












This may be a long day

symbolipoint

ugeminorum has it right. the exponent 4 belongs to the 2. That part must be evaluated first. [tex] \[
- 2^4
\]
[/tex] indicates the negative of two to the fourth power; note no grouping symbols, so you do the exponentiation first.
[tex] \[
- 2^4 = - (2)(2)(2)(2)
\]
[/tex]

Phykick

I thought this was all just levity from all those involved........
The original was (-2)^4 way back in post #13
Please move on from this.

I found this forum looking for info about the HP 50g as my 48 has gone bad.

If anyone has more of the good, the bad and the ugly of the new flavor I would like to here from you.






My degree is in ARTHEYALLINSANEORISITME

dtl42

Hey everyone, I've been trying to install the RPN program on my Ti-89 Titanium, and everytime I try to run it, the calculator freezes and I am forced to reset, anyone want to help me through this?

Tom McCurdy

Ti-89 Ftw

Math Jeans

Well, I personally use the Ti-Voyage 200. Its the most advanced thing Ti has got on the market. Thats your best bet for having the functions you want.

271828

Well, I'm coming into the thread very late, but have a funny anecdote that might be worth sharing. Full disclosure: I've been an HP calculator fanatic for almost 20 years now and think RPN is the coolest thing since sliced bread, LOL.

Last year, I taught an undergrad class for the first time and had 37 junior and senior engineering students. Every single one of them used a TI-[whatever] and not a single one had an HP. Anyway, on their second exam, they had to solve an equation that took an entire line to write and had three square roots, two of them nested. As I graded it, I noticed that almost every single one of them screwed up punching it through their calculator. Turns out that 3/37 were able to do it without a mistake. Most of them were writing it out in 2-3 lines, etc. I knew I'd catch grief over that, so I punched it through using my HP48G calculator, which is of course RPL (like RPN). I did it three times in a row without an error, averaging 22 sec.!! Of course, I had that ready for them the next class, LOL.

Granted, I was using my calculator when most of them were in preschool, but supposedly younger folks are better at newfangled gadgets, right?

It's hard to explain to non-RPN users why RPN is better, but it really is. I've never met anybody who gave it a fair try for 2-3 weeks who didn't switch over.

becca4

I agree. I have the hp 50g and am very happy with it, once I went rpn, I never went back.

Well, I did at times when the 50g's symbolic solving didn't sit so well with the professors, but honestly, it's one of the best investments I've ever made. I'd recommend it for people going into engineering.

Adrian4English

I've been using HP's for the last zillion years (or at least since the first HP 35). RPN, when I first met it was confusing but after 10 minutes or so playing with it, it made complete sense to me and I found it easy to use. I have been using HP calculators ever since. Despite my moniker, I'm a professional engineer and would not be without one.
The HP50g is my latest (the last, an HP48sx died on me last year after 20 years of faithful service) and so far the best calculator I have used.
If you like algebraic input, it does have it. Indeed the user manual gives many more examples on how to use algebraic mode than it gives for RPN mode.
My only complaint is that the user manual only brushes the surface of what it can do. The user manual that comes with the machine is some 880 pages long.
You can write some very sophisticated programmes using the built in RPL language but you must know RPN and how the stack operates to use it efficiently.
The ten or fifteen minutes you spend learning RPN is a real investment. Once you know how to use it, you'll never regret it!

stewartcs

Most Calculus courses won't let you use a calculator that perfoms integrals and differentials on exams. You might want to consider that before spending the $$ on either one...or check with your professor to see if they allow them.

SA Penguin

At the risk of incurring the wrath of everyone, may I point out how this up how RPN is different?

IF you think the minus is part of the number (-2) you solve with: 2 +/- ENTER 4 y^x ...and get 16

BUT- if you decide the - is an operation, and to be done last, you enter: 2 ENTER 4 y^x +/- ...and get -16

The RPN makes no assumptions, it's up to YOU to enter the equation correctly. Whereas the TI made an assumption which sparked this lively debate.

While reading past posts, for some reason I kept thinking of the infamous question - the airspeed of an unladen swallow.
African or European ? (24 mph for European... http://www.style.org/unladenswallow/ )

goodlun

Wow someone who got it right I think they are confusing Negative(which is a notation) with Minus(which is an operation). Negative means the number is sitting its value left on the number scale of the number 0. Minus means your doing an operation that will move the number to the left of where it is. -2 is a real number we know its the negative value because of the (-) in front of it. While (-1)(2)= -2 the -1*2 operation has already been completed. In the case of -X^4 the actually equation looks like this (-1)X^4 if the value of X was say -2 they the answer would be -16. If the equation was X^4 and the value of X is still -2 the answer is going to be 16.