^interesting
just sayin
Forum Index > General Forum |
-{Cake}-
United States217 Posts
^interesting just sayin | ||
naptiem
United States21 Posts
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Ceril
Sweden1343 Posts
It does remind me of something to: If your getting confused by all the paranthesis, rewrite the question and add the silent operators. Dont remember who said that, but darn, I should've remembered his advice | ||
space_yes
United States548 Posts
On April 08 2011 11:49 timothyarm wrote: Show nested quote + On April 08 2011 11:47 jtan wrote: On April 08 2011 11:44 Zeke50100 wrote: On April 08 2011 11:42 jalstar wrote: On April 08 2011 11:38 Zeke50100 wrote: AN EXAMPLE OF AN AMBIGUOUS QUESTION: What is the square-root of 4? See how that's ambiguous? See how it cannot compare to the OP's poll-question? Ok, you don't know what ambiguous means. Hint: it doesn't mean "multi-valued". Methinks you don't know what it means. It can be interpreted as +2, -2, +2/-2, or as an invalid question. Actually, no. It's 2. Go read a math book. sqrt(x^2) = +/-x, does it not? :-) Okay, I won't erase that, but...I'll correct what I meant. Lol. (-x)^2 = (x)^2 = x^2 Don't confuse functions with scalars... | ||
moltenlead
Canada866 Posts
Nice trick, but doubt it would happen when the equation is in proper and clear syntax. | ||
yankfan
United States10 Posts
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mcc
Czech Republic4646 Posts
On April 08 2011 11:25 space_yes wrote: The poll questions test whether you implemented the logic of order of operations correctly. It's not ambiguous at all; it only seems that way if you don't know you need to use order of operations or you don't know how. With order of operations there is no possible way to interpret the question except as .5x. It's ok to be wrong guys ^_^ Rules are not laws. Rules have to be agreed upon explicitly or implicitly. No mathematician(..) if he really wanted to communicate anything would write 48/2(9+3) , because he knows it will be ambiguous for someone due to some regional or community quirks in notational rules. The order of operations you are using is not universal as it is not used and agreed upon by everybody. | ||
jtan
Sweden5891 Posts
On April 08 2011 11:56 Severedevil wrote: Show nested quote + On April 08 2011 11:52 jtan wrote: On April 08 2011 11:49 timothyarm wrote: On April 08 2011 11:47 jtan wrote: On April 08 2011 11:44 Zeke50100 wrote: On April 08 2011 11:42 jalstar wrote: On April 08 2011 11:38 Zeke50100 wrote: AN EXAMPLE OF AN AMBIGUOUS QUESTION: What is the square-root of 4? See how that's ambiguous? See how it cannot compare to the OP's poll-question? Ok, you don't know what ambiguous means. Hint: it doesn't mean "multi-valued". Methinks you don't know what it means. It can be interpreted as +2, -2, +2/-2, or as an invalid question. Actually, no. It's 2. Go read a math book. sqrt(x^2) = +/-x, does it not? :-) Okay, I won't erase that, but...I'll correct what I meant. Lol. (-x)^2 = (x)^2 = x^2 sqrt(x^2) = |x| for all real x, no ambiguity in any case. Maybe this should have been the poll also as there seems to be some different opinions 'sqrt' is the principal square root function. It is not 'the' square root of a positive number... it is ONE of the TWO square roots of a positive number. Specifically, it's the positive one. Apologies, I thought he was refferring to sqrt, language differences... | ||
MajorityofOne
Canada2506 Posts
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SirKibbleX
United States479 Posts
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DarkPlasmaBall
United States42207 Posts
On April 08 2011 05:35 Retgery wrote: Oh dear...who picked 288? The point of Bedmas is to get rid of brackets first. Oh dear: 1. The answer is 288 >.> 2. Bedmas? Brackets? Those aren't brackets lol ( ) are parentheses [ ] are brackets { } are braces It's called PEMDAS Parentheses, Exponents, Multiplication/ Division, Addition/ Subtraction (Please Excuse My Dear Aunt Sally) I'm getting a masters degree in math education in a month... I can't wait to start teaching kids! | ||
jtan
Sweden5891 Posts
On April 08 2011 11:37 jalstar wrote: Linear Algebra, Real Analysis, Differential Equations, Nonlinear Dynamics, Game Theory, and Complex Analysis, all at UCLA. On April 08 2011 11:39 space_yes wrote: I am double majoring in applied computational and mathematical sciences (ACMS) and statistics at the University of Washington. I've taken your first year calculus run (differential, integral and multi-variable), vector calculus (different universities have different names for this course, covers Stokes Theorem, divergence, curl etc), ordinary differential equations, partial differential equations, linear algebra, and numerical analysis so far. I have about two years left. Looking forward to my discrete math classes next fall On April 08 2011 11:45 MadVillain wrote: I'm a Comp Sci & Chem E major at University of Minnesota, I've taken: Multivariable Calc, Linear Algebra, An introductory course to Combinatorics/Set Theory/A couple other things, Numerical Analysis.. some others only a sophmore though so I have a lot ahead thanks! I just finished my masters thesis on algebra. | ||
mcc
Czech Republic4646 Posts
On April 08 2011 11:35 ]343[ wrote: So I just polled some more MIT math/physics majors. One said 288, one said 2, and one (who was incidentally top 14 on the Putnam exam...) said 72 because he hasn't seen a division sign written like that in years and thought it was a plus sign. I think the problem is that when the division sign is written that way, people who do math automatically convert it to a fraction bar--after all, that's what ÷ means: the dots represent expressions and the -- is a fraction bar. That might also be a factor, I first thought that strange sign meant division modulo But than you check possible answers and it is clear that it cannot be. | ||
StarStruck
25339 Posts
On April 08 2011 11:39 Scaramanga wrote: How on earth did this thread get 44 pages, are people that silly? I love rhetorical questions. Yes, all of us do silly things and we like to think we know a lot when we really don't. With that said, this thread has been highly entertaining. =D My mom told me a story once. Her father taught math at U of T and as such, he taught her at an early age. Anyway, she got a B+ one time. Came home and said something along the lines of, "Dad, my teacher said you were wrong!" His face was red. Why did the teacher mark her solution wrong? She didn't do what the question had asked. Instead she applied an advance theorem her Dad taught her and not what was in the textbook. As far as I'm concerned there was no confrontation, but to this day I still find it funny as hell. My mother's side of the family has a very strong foundation in math. I'll let you guys know the results. Updates: Mom and Dad got it at 288. Cousins got 288. Both uncles got 288. | ||
space_yes
United States548 Posts
On April 08 2011 12:05 DarkPlasmaBall wrote: Show nested quote + On April 08 2011 05:35 Retgery wrote: Oh dear...who picked 288? The point of Bedmas is to get rid of brackets first. Oh dear: 1. The answer is 288 >.> 2. Bedmas? Brackets? Those aren't brackets lol ( ) are parentheses [ ] are brackets { } are braces It's called PEMDAS Parentheses, Exponents, Multiplication/ Division, Addition/ Subtraction (Please Excuse My Dear Aunt Sally) I'm getting a masters degree in math education in a month... I can't wait to start teaching kids! Don't tell me you picked 1/(2x)? | ||
Rkie
United States1278 Posts
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Phaded
Australia579 Posts
On April 08 2011 12:05 DarkPlasmaBall wrote: Show nested quote + On April 08 2011 05:35 Retgery wrote: Oh dear...who picked 288? The point of Bedmas is to get rid of brackets first. Oh dear: 1. The answer is 288 >.> 2. Bedmas? Brackets? Those aren't brackets lol ( ) are parentheses [ ] are brackets { } are braces It's called PEMDAS Parentheses, Exponents, Multiplication/ Division, Addition/ Subtraction (Please Excuse My Dear Aunt Sally) I'm getting a masters degree in math education in a month... I can't wait to start teaching kids! It all depends on where you live. ( ) is brackets in british / commonwealth usage [ ] are denoted as square brackets { } are braces, or in some primary schools, squiggly brackets | ||
shinosai
United States1577 Posts
On April 08 2011 11:55 Zeke50100 wrote: Show nested quote + On April 08 2011 11:53 shinosai wrote: On April 08 2011 11:38 Zeke50100 wrote: AN EXAMPLE OF AN AMBIGUOUS QUESTION: What is the square-root of 4? See how that's ambiguous? See how it cannot compare to the OP's poll-question? On April 08 2011 11:38 shinosai wrote: On April 08 2011 11:35 Zeke50100 wrote: On April 08 2011 11:34 shinosai wrote: On April 08 2011 11:23 StarStruck wrote: On April 08 2011 11:09 shinosai wrote: Hmm. I got it wrong, but I'm not really bothered by it. My calculus book never had such poor notation. Parenthesis are your friend. I think this thread really just amounts to people being annoyed by bad notation (not necessarily wrong, but bad nonetheless). In the math classes that I took, using parenthesis to make your work clear and concise was mandatory. That's calculus though. When you see a problem written in the following you have to ask yourself. What is this problem asking? There are only 3 things. Brackets, division and multiplication. What does this tell you? One of the first things you learned about operations. What you see is what you get. Poor form or not. Sure, it's poor form to the scholarly eye, but you should have an idea of what they're asking based on the shitty form alone. There's a reason why you don't see ÷ used so much anymore! That's like the first indication. Grade school math. Order of operations! :O The fact you guys are saying it's ambiguous should tell you it's an elementary question asking you to use the order of operations. I didn't say it was ambiguous, but it is bad notation. Now, I know you think this should make me feel bad because this is grade school math. However, it doesn't, because the practical application of bad notation is zero. What I'm trying to say is, bad notation like this is something you will almost never come across. It's like making fun of someone for misinterpreting an English sentence that was written with an odd word order. We come across these all the time, and instead of making fun, why not just clarify by writing in standard word order? I'm never going to have to apply trigonometric identities in real life. Does that mean I should ignore its existence? Trigonometric identities have useful functions for solving problems. Please detail me on what exactly is useful about bad notation in comparison to standard notation? This is one that I would love to hear. I never said bad notation was useful. You, however, are saying that you shouldn't need to know bad notation at all, essentially ignoring that it is completely legitimate and legal. You made an analogy comparing bad notation to something useful. I thought it was clear that you thought bad notation was useful. My bad. And since it is not practically useful, I'm not sure why it being legitimate and legal is relevant. I'm sure there are a lot of things in this world that are legitimate and legal that you and I both don't have a care in the world about. I fail to see why I should feel any worse about misinterpreting a poorly notated math problem than misinterpreting a poorly ordered English sentence. Both happen occasionally, but neither are necessary for a high level understanding of mathematics or English. Anyways, your argument mostly seems to stem from the fact that you think people have a problem understanding order of operations, but mostly people just have a problem with the grouping notation. I understand the order of operations perfectly fine, and given standard notation, would never have a problem with such a thing. Given that standard notation is, well, standard, I fail to see the importance of this legitimate, legal, and useless "bad" notation. This is the kind of argument players who lose to Bronze players in SC2 say to "cover their asses". It's not valid to say that something is nonstandard, therefore should not be given any significance. Everybody is expected to know that 2/2 is equal to 1, even if it's less standard to be written as 2/2. It's not only nonstandard; lack of clarity has no practical value, either. I think you are mistaken in your comparison of failing to distinguish terms with parenthesis to showing that (2/2)=1. For the former is something that would be frowned upon due to lack of clarity, the latter being not only standard division but relevant to the axiom of extensionality as well. | ||
moltenlead
Canada866 Posts
On April 08 2011 12:05 DarkPlasmaBall wrote: Show nested quote + On April 08 2011 05:35 Retgery wrote: Oh dear...who picked 288? The point of Bedmas is to get rid of brackets first. Oh dear: 1. The answer is 288 >.> 2. Bedmas? Brackets? Those aren't brackets lol ( ) are parentheses [ ] are brackets { } are braces It's called PEMDAS Parentheses, Exponents, Multiplication/ Division, Addition/ Subtraction (Please Excuse My Dear Aunt Sally) I'm getting a masters degree in math education in a month... I can't wait to start teaching kids! I have had 6 math teachers in a course with algebra and they all had different names. Fully depends on the location where you learned it. | ||
jtan
Sweden5891 Posts
On April 08 2011 12:09 Rkie wrote: Well, I and my amazing reading abilities decided that the 2 was in the parentheses as well, so I chose 2. After I voted, I saw my mistake, and just laughed. I am glad I am going into a math career... Don't worry, this isn't a test of mathematical ability | ||
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