EPTOn April 08 2011 07:52 Mailing wrote:
Holy shit, even the internet doesn't know o_o
![[image loading]](http://imgur.com/HvN5t.jpg)
Holy shit, even the internet doesn't know o_o
That's because the first picture isn't representing 48/2(9+3), it's representing 48/(2(9+3))
A Simple Math Problem? - Page 27
| Forum Index > General Forum |
|
[wh]_ForAlways
United States235 Posts
That's because the first picture isn't representing 48/2(9+3), it's representing 48/(2(9+3)) | ||
|
GizmoPT
Portugal3040 Posts
this is win sir.. | ||
|
Pufftrees
2449 Posts
On April 08 2011 07:13 Milkis wrote: whoever writes notation like that should be shot since it can be ambiguous! Lol what is ambiguous about it? | ||
|
Nesserev
Belgium2760 Posts
| ||
|
munchmunch
Canada789 Posts
On April 08 2011 08:02 Zeke50100 wrote: Being accustomed to the omission of parentheses doesn't make it right  No, but aesthetics can be a good reason. | ||
|
legatus legionis
Netherlands559 Posts
On April 08 2011 07:55 FrozenPanDA wrote: No sir, I am not kidding. To get 288, the MAJORITY vote, you have to do (48/2)(12) which is the same as (1/2)*x, the MINORITY vote. To get 2, which was the MINORITY vote, you have to do (48)/(2*12) which is the same as 1/(2*x) if let 48=1 and (9+3)=x, and is also the MAJORITY vote Yea, I thought that was really interesting. Answers go one way but then the method goes another way Also because I was just thinking about the ÷ symbol. I looked it up and if this is correct: http://www.thefreedictionary.com/division signs 1. The symbol (÷) placed between two quantities written on a single line to indicate the division of the first by the second. 2. The symbol (/) placed between two quantities written horizontally, as in 2/3 , or the symbol (-) placed between two quantities written vertically, as in 2/3 , to indicate a fraction. The idea behind this was that because I know the ÷ exists. Doesn't the dots indicate to take only those instances that are connected? And then the slash is actually the fraction? Or in any case there must be made a difference between these. Even when it's the "single line math". So pretty much, I think the slash actually means everything after the slash becomes the denominator. Where as the ÷ connect what comes before and afterwards and make it into a new thing. Anyway whatever, topic goes way to fast and I've read enough nasty remarks for the day. Edit: hmm, to come back maybe its the other way around, where the slash indicating the fraction makes it so that the fraction is it's own thing. As we have seen many times where the ( ) gets seperated and multiplied by the / fraction. ! | ||
|
thesideshow
930 Posts
yup. Just because its so often a constant acting on a variable. | ||
|
Pufftrees
2449 Posts
On April 08 2011 08:04 Nesserev wrote: The main thing to look out for is that you don't make any mistakes concerning the 'associativity' of any multiplication/division : a*b/c = a/c*b so : 3*5/4 = 3/4*5 = 3.75 If we apply this rule on the first question, the answer has to be : 48/2*12 = 48*12/2 = 288 24*12 = 48*6 = 288 <-- right answer The right answer of the second question is (1/2)X, this can be shown clearly by giving X a certain value, for example : X=5 if : 1/2*5 = 1*5/2 = 2.5 then : 1/(2X) = 1/(2*5) = 0.1 <-- wrong answer (1/2)X = (1/2)5 = 2.5 <-- right answer Lol why go through all that explanation when you could just say, it's Math, that's how it works. | ||
|
GizmoPT
Portugal3040 Posts
48/2(9+3) (48/2)(9+3) 48/2*(9+3) 48/(2(9+3)) | ||
|
Pufftrees
2449 Posts
Ok I repeat, what is ambiguous about it? There is 1 answer for each way its written, there is no way you would get it wrong if you knew math. | ||
|
lvlashimaro
United States91 Posts
48 *(9+3) -------------- 2 By so doing, it doesn't matter if you divide 48/2 first or 12/2 first, as long as you obey the convention of parentheses first, you'll get the same answer. Also, you can't always assume cos2x implies cos(2x). cos(2) * x is just as viable. I abuse the power of parentheses because it makes life a lot easier, and I can break up large problems into a lot of smaller ones. Especially when you have so many variables and constants you're worrying about, one small mistake = drastically different outcome that doesn't make physical sense. O_O P.S. since there seem to be some math gurus here, I'm a biomedical engineer, and I'm wondering if someone can help explain and derive the Navier-Stokes Equation. Namely, how did they get rid of the necessity of mass and density? O_O PM please =[. | ||
|
Zeke50100
United States2220 Posts
On April 08 2011 08:03 Blisse wrote: Oh shit. Division isn't commutative. Good game guys. There is no correct answer in this case. Stop following BEDMAS. It was made up by grade school teachers to help you understand the order of operations. It doesn't work in extreme cases because there is no correct way to interpret the equation. Essentially, 2/3*4 is not the same as (2)(1/3)(4) which it isn't the same as (2/3)(4) which isn't the same as (2)/(3*4). You can't simply convert division into fractional form because the math symbols aren't clear enough. In written form, you interpret the question based on what the symbols show. On one text line, that's impossible to convey without parenthesis. The best example would be 2/3/4. If you did it (2/3)/4, I haven't specified which / is larger. The computer reads it to the best of its ability. It is limited by computer notation. There is no difference between / and a larger / for a computer, which is why it simply reads it front to end after the regular operations. The bigger question is then: Do we treat this as a written, typed or oral question? The problem is that there IS a way, and ONLY one way, to interpret it correctly. If you follow PEMDAS, you will get the right answer, every single time. The problem is that people don't realize that fractions with multiple terms cannot exist without parenthesis when a "/" is used. I treat it as both a written and a typed question. Written doesn't apply to only handwritten things :D | ||
|
rackdude
United States882 Posts
On April 08 2011 08:00 crate wrote: And you would believe anyone would write the expression in the OP in any accurate paper/article/book? It would never make it into print unless it's presented as an example of purposely misleading notation. edit: @ Rackdude: Clearly that's cosh(p/2) Haha, I like it. Oh yeah, question, did you go to Oberlin? | ||
|
GizmoPT
Portugal3040 Posts
On April 08 2011 08:06 Pufftrees wrote: Ok I repeat, what is ambiguous about it? There is 1 answer for each way its written, there is no way you would get it wrong if you knew math. so you saying i dont know math ? :o | ||
|
thesideshow
930 Posts
On April 08 2011 08:06 Pufftrees wrote: Ok I repeat, what is ambiguous about it? There is 1 answer for each way its written, there is no way you would get it wrong if you knew math. because the question in the OP can be interpreted as any of the above. | ||
|
garbanzo
United States4046 Posts
On April 08 2011 08:03 Blisse wrote: Oh shit. Division isn't commutative. Good game guys. There is no correct answer in this case. Stop following BEDMAS. It was made up by grade school teachers to help you understand the order of operations. It doesn't work in extreme cases because there is no correct way to interpret the equation. Essentially, 2/3*4 is not the same as (2)(1/3)(4) which it isn't the same as (2/3)(4) which isn't the same as (2)/(3*4). You can't simply convert division into fractional form because the math symbols aren't clear enough. In written form, you interpret the question based on what the symbols show. On one text line, that's impossible to convey without parenthesis. The best example would be 2/3/4. If you did it (2/3)/4, I haven't specified which / is larger. The computer reads it to the best of its ability. It is limited by computer notation. There is no difference between / and a larger / for a computer, which is why it simply reads it front to end after the regular operations. The bigger question is then: Do we treat this as a written, typed or oral question? 2/3*4 = (2)(1/3)(4) = (2/3)(4) != 2/(3*4) Three of those are exactly the same. The way you wrote it is completely unambiguous. The ambiguity in the original statement is in the omission of a multiplication symbol. Having back to back parentheses like that, e.g. (2)(3), counts as a multiplication symbol. | ||
|
Pufftrees
2449 Posts
No, I am saying, there is nothing ambiguous about it. Those could all be separate exam questions, and there would be ONE answer, and you couldn't use the excuse "its ambiguous" to your teacher. | ||
|
Mailing
United States3087 Posts
On April 08 2011 08:03 [wh]_ForAlways wrote: That's because the first picture isn't representing 48/2(9+3), it's representing 48/(2(9+3)) Again, the same 48÷2(9+3) input was used on both. If the first one changed it to that form, it's because the people who programmed that site (probably people very good at math) deemed it so. I cannot explain why, but it's just further evidence that there are different interpretations. | ||
|
Torte de Lini
Germany38463 Posts
He's saying you're not mathematically deducing the answer but going by first glance. Don't incite an insult. | ||
|
munchmunch
Canada789 Posts
+ Show Spoiler + On April 08 2011 08:06 Zeke50100 wrote: The problem is that there IS a way, and ONLY one way, to interpret it correctly. If you follow PEMDAS, you will get the right answer, every single time. The problem is that people don't realize that fractions with multiple terms cannot exist without parenthesis when a "/" is used. I decided not to tell you to brush up on your reading comprehension in my last reply to avoid being snarky. But now it is unavoidable: put aside your amazing grade school education and read the thread. | ||
| ||
