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On April 08 2011 08:52 garbanzo wrote:Show nested quote +On April 08 2011 08:50 Mailing wrote:On April 08 2011 08:49 Zeke50100 wrote:On April 08 2011 08:47 garbanzo wrote:On April 08 2011 08:39 Zeke50100 wrote:On April 08 2011 08:38 Entropic wrote:
lol what a shittily written and ambiguous expression (as many have noted already) It's 0% ambiguous, but 100% a test of your understanding of math. You really don't see how 1/4*(3+2) is less ambiguous than 1/4(3+2)? How about 1/2(a+b) versus 1/2*(a+b)? There is only one correct way to interpret them. No idea how it's ambiguous. Personal lack of knowledge or personal confusion do not equal ambiguity. If you can find some evidence of this.. Yes, I would like some source that it can definitively only be read one way. And you didn't really answer my question. If you were to ask someone a question, and you wanted absolutely no confusion, then would you consider choosing one notation over the other? I think you're lying to yourself if you say otherwise.
I don't get how "these two things are exactly the same" do not equate to "these two things are interchangeable, and therefore one is no more ambiguous than the other" in your mind.
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PEMDAS for Life
Parenthesis
Exponent
Multi,
Division
Addition
Subtraction
I think I got them right and I've only finished H.S.
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B (brackets) E (exponents) D (division) M (multiplication) A (addition) S (subtraction) from fucking middle school. 288 ezpz
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On April 08 2011 08:54 munchmunch wrote:Show nested quote +On April 08 2011 08:44 Zeke50100 wrote:On April 08 2011 08:40 munchmunch wrote:On April 08 2011 08:18 MandoRelease wrote:On April 08 2011 08:04 munchmunch wrote:On April 08 2011 08:02 Zeke50100 wrote:On April 08 2011 08:01 munchmunch wrote:
[
Not due to laziness at all, actually. Granted, it would be incorrect to omit the parentheses in many contexts, but in any context where it can be expected to be unambiguous to the reader, it would be recommended to any mathematical writer to drop the parentheses for aesthetic reasons.
Being accustomed to the omission of parentheses doesn't make it right  No, but aesthetics can be a good reason. Not in anything that does not involves advanced mathematics. I certainly agree that you sometime need to lower your accuracy when you write advanced mathematical paper in order to make it understandable. It is not the case for basic math like trigonometry and basically anything put on a non mathematical forum. For these, it's only lazyness because adding parentheses here and there would not make it any less clear, so aesthetics is not always a good reason. Ok, I guess I should write a longer post on my thoughts on this subject. Recall that the original subject was about whether something like cos 2x is an incorrect statement for cos(2x). There is no doubt that it is helpful for beginning students to put the brackets in. And every student should understand that there is an unambiguous idea, essentially "perform the multiplication 2 * x and then evaluate the function cos at 2*x", which can be communicated unambiguously by adding the brackets. It would also be nice if people knew that this statement can be made so clear that a computer can understand it, although a computer might require something like "cos(2*x)" or "(cos (* 2 x))". However, none of that means that cos 2x is wrong! My emotion towards people who perpetuate this sentiment is similar to that contained in Stephen Fry's language rant. As long as the notation is understood, it is never wrong to write cos 2x. And it can sometimes be better to write cos 2x. In differential geometry, for example, if you add parentheses everywhere they might be required, the large amount of parentheses can impede readability. This is not to contradict you; no doubt cos(2x) is a better choice for a homework thread on TL, for example. But that just means that other considerations are preeminent in that situation. The problem is that cos2x is NOT equal to cos(2x). It IS wrong. It's not comparable to Fry's language rant at all, because there is a right and a wrong when it comes to math and mathematical notation. This is exactly the sentiment that I find disgusting. I mean, I agree with you to a point. But the idea that cos 2x is not equal to cos(2*x), when many people use cos 2x without the slightest ambiguity, is perverse to me. But let's agree to disagree. If we keep arguing, it can only go two ways: into ad hominem, or into a dick showing contest, neither of which is agreeable to me. And I hope you saw my apology for starting on the ad hominem's earlier.
They use cos2x without ambiguity because people understand what is right. I would be fine with that if EVERYBODY understood what is right, but obviously not. People who pass on the incorrect notations may not have bad intentions (I omit parentheses myself sometimes when communicating with somebody who knows what I mean), but people who don't know better pick up on it and think it's right. They try putting it into a calculator, and guess what happens?
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On April 08 2011 08:59 Zeke50100 wrote:Show nested quote +On April 08 2011 08:52 garbanzo wrote:On April 08 2011 08:50 Mailing wrote:On April 08 2011 08:49 Zeke50100 wrote:On April 08 2011 08:47 garbanzo wrote:On April 08 2011 08:39 Zeke50100 wrote:On April 08 2011 08:38 Entropic wrote:
lol what a shittily written and ambiguous expression (as many have noted already) It's 0% ambiguous, but 100% a test of your understanding of math. You really don't see how 1/4*(3+2) is less ambiguous than 1/4(3+2)? How about 1/2(a+b) versus 1/2*(a+b)? There is only one correct way to interpret them. No idea how it's ambiguous. Personal lack of knowledge or personal confusion do not equal ambiguity. If you can find some evidence of this.. Yes, I would like some source that it can definitively only be read one way. And you didn't really answer my question. If you were to ask someone a question, and you wanted absolutely no confusion, then would you consider choosing one notation over the other? I think you're lying to yourself if you say otherwise. I don't get how "these two things are exactly the same" do not equate to "these two things are interchangeable, and therefore one is no more ambiguous than the other" in your mind.
LOL, I read that and thought "What a good post, well said!" Then I reread it and realized you were saying the exact opposite of what I thought. I guess a Zeke50100 is an anti-munchmunch.
And to jump into that conversation, "the same" on a semantic level is not the same as being "the same" on a syntactic level.
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On April 08 2011 08:59 Zeke50100 wrote:Show nested quote +On April 08 2011 08:52 garbanzo wrote:On April 08 2011 08:50 Mailing wrote:On April 08 2011 08:49 Zeke50100 wrote:On April 08 2011 08:47 garbanzo wrote:On April 08 2011 08:39 Zeke50100 wrote:On April 08 2011 08:38 Entropic wrote:
lol what a shittily written and ambiguous expression (as many have noted already) It's 0% ambiguous, but 100% a test of your understanding of math. You really don't see how 1/4*(3+2) is less ambiguous than 1/4(3+2)? How about 1/2(a+b) versus 1/2*(a+b)? There is only one correct way to interpret them. No idea how it's ambiguous. Personal lack of knowledge or personal confusion do not equal ambiguity. If you can find some evidence of this.. Yes, I would like some source that it can definitively only be read one way. And you didn't really answer my question. If you were to ask someone a question, and you wanted absolutely no confusion, then would you consider choosing one notation over the other? I think you're lying to yourself if you say otherwise. I don't get how "these two things are exactly the same" do not equate to "these two things are interchangeable, and therefore one is no more ambiguous than the other" in your mind.
Okay, I concede. Next time a peer reviewer in a journal or professor tells me to rewrite an equation because it's ambiguous, I'll just tell them to learn their order of operations.
Edit: My comment isn't meant to be sardonic. I'm just trying to point out that just because there is a grand rule that you can always refer to, e.g. order of operations, doesn't mean that certain ways of writing an equation are superior because they remove ambiguity.
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This thread makes me both super rage and facepalm. Pretty sure most university math kids will see 1/2x as 1/(2x). Either way, I always err on the side of more brackets to be clear.
Also someone post the link to the bodybuilding thread? I don't see it anywhere?
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You really don't see how 1/4*(3+2) is less ambiguous than 1/4(3+2)?
Honestly, for me, those have a similar level of confusion.
You should write (1/4)(3+2) to disambiguate.
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this is like asking what word represents "you are", you're or your?
given the correct context "your" can easily be interpreted as "you're" but that doesn't mean "your" is correct.
example: your wrong.
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On April 08 2011 09:04 buhhy wrote:
This thread makes me both super rage and facepalm. Pretty sure most university math kids will see 1/2x as 1/(2x). Either way, I always err on the side of more brackets to be clear.
Also someone post the link to the bodybuilding thread? I don't see it anywhere?
This thread makes it pretty clear that different countries teach different math... which is fucking weird.
In the US, 1/2x = 1/(2x)... in some it = .5x
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On April 08 2011 09:06 Mailing wrote:Show nested quote +On April 08 2011 09:04 buhhy wrote:
This thread makes me both super rage and facepalm. Pretty sure most university math kids will see 1/2x as 1/(2x). Either way, I always err on the side of more brackets to be clear.
Also someone post the link to the bodybuilding thread? I don't see it anywhere? This thread makes it pretty clear that different countries teach different math... which is fucking weird. In the US, 1/2x = 1/(2x)... in some it = .5x
But really, no one should be that ambiguous. If they are, you ask them what it he is referring to.
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48/2(9+3)
If 2(9+3) is computed first it has to satisfy the laws of the natural numbers.
So 48/18 + 6 should equal 48/24 by the distributive property.
But 9.6666667 != 2.
So by the natural number system properties, 48/2 must be computed before 2(9+3), giving you 288.
All of those who answered "because that's the way it is!" without any sort of proof attempt make me 
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On April 08 2011 09:04 gyth wrote:Honestly, for me, those have a similar level of confusion. You should write (1/4)(3+2) to disambiguate.
To me there is no ambiguity because there is a definitive multiplication symbol. But yes, if I were asked if my way or your way is more ambiguous, I would say that the way you wrote it is clearer.
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On April 08 2011 09:06 Mailing wrote:Show nested quote +On April 08 2011 09:04 buhhy wrote:
This thread makes me both super rage and facepalm. Pretty sure most university math kids will see 1/2x as 1/(2x). Either way, I always err on the side of more brackets to be clear.
Also someone post the link to the bodybuilding thread? I don't see it anywhere? This thread makes it pretty clear that different countries teach different math... which is fucking weird. In the US, 1/2x = 1/(2x)... in some it = .5x
that's wrong. generally books will write it as ½x and use / to only mean simple division but just because you are used to a certain method of interpreting the symbol doesn't mean it is empirically correct. when you read single line equations the standard interpretation follows the order of operations.
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The moral of the story is: don't do math.
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On April 08 2011 09:07 jalstar wrote:48/2(9+3) If 2(9+3) is computed first it has to satisfy the laws of the natural numbers. So 48/18 + 6 should equal 48/24 by the distributive property. But 9.6666667 != 2. So by the natural number system properties, 48/2 must be computed before 2(9+3), giving you 288. All of those who answered "because that's the way it is!" without any sort of proof attempt make me
Why did the parenthesis go away when you distributed the 2?
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Why are people so surprised by how many people got this wrong? From my experience the vast majority of people are horrible at math, no matter how simple it may seem to those who understand it. All you need to know to solve those equations is BEDMAS which is an elementary school concept.
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On April 08 2011 09:00 Grobyc wrote:
B (brackets) E (exponents) D (division) M (multiplication) A (addition) S (subtraction) from fucking middle school. 288 ezpz
Maybe, we were taught : brackets > exponents > (multi, div) > (add, sub). And if you have something ambiguous , just use the brackets. But in reality I never cared and never needed to solve this problem once in my years of math in uni, because I nearly never used or saw division written on one line in practice, and if it was it was clear from context or there were brackets.
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On April 08 2011 08:40 munchmunch wrote:Show nested quote +On April 08 2011 08:18 MandoRelease wrote:On April 08 2011 08:04 munchmunch wrote:On April 08 2011 08:02 Zeke50100 wrote:On April 08 2011 08:01 munchmunch wrote:
[
Not due to laziness at all, actually. Granted, it would be incorrect to omit the parentheses in many contexts, but in any context where it can be expected to be unambiguous to the reader, it would be recommended to any mathematical writer to drop the parentheses for aesthetic reasons.
Being accustomed to the omission of parentheses doesn't make it right No, but aesthetics can be a good reason. Not in anything that does not involves advanced mathematics. I certainly agree that you sometime need to lower your accuracy when you write advanced mathematical paper in order to make it understandable. It is not the case for basic math like trigonometry and basically anything put on a non mathematical forum. For these, it's only lazyness because adding parentheses here and there would not make it any less clear, so aesthetics is not always a good reason. Ok, I guess I should write a longer post on my thoughts on this subject. Recall that the original subject was about whether something like cos 2x is an incorrect statement for cos(2x). There is no doubt that it is helpful for beginning students to put the brackets in. And every student should understand that there is an unambiguous idea, essentially "perform the multiplication 2 * x and then evaluate the function cos at 2*x", which can be communicated unambiguously by adding the brackets. It would also be nice if people knew that this statement can be made so clear that a computer can understand it, although a computer might require something like "cos(2*x)" or "(cos (* 2 x))". However, none of that means that cos 2x is wrong! My emotion towards people who perpetuate this sentiment is similar to that contained in Stephen Fry's language rant. As long as the notation is understood, it is never wrong to write cos 2x. And it can sometimes be better to write cos 2x. In differential geometry, for example, if you add parentheses everywhere they might be required, the large amount of parentheses can impede readability. This is not to contradict you; no doubt cos(2x) is a better choice for a homework thread on TL, for example. But that just means that other considerations are preeminent in that situation.
Well, you think that if a notation is understood then it is correct. While I absolutely cannot disagree with that, my problem is that "cos 2x" is not an actual accurate mathematical notation. My point is that it can be ambiguous, thus is not suited to be used, and only results from lazyness.
The reason for this is the following : I need to be able to use notations in any context, and I am not able to with "cos 2x".
Obviously "cos 2x f(x)" is very ambiguous and one would prefer it to be written "cos(2x)f(x)" (f being a random function).
"cos 2x" is very situationnal, you can basically only write that in a trigonometric identity, which is all my problem. If something cannot be used in any context because it would raise ambiguity, then it should mean that the notation is not correct.
People understanding it in one particular formula does not make the notation correct.
I feel if we keep discussing it we'll just start again from the top.
EDIT : Yup, just read your previous posts. I agree with you, let's disagree.
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EPT
