Thread: "I Love College"

11/08/2012 4:10pm, #2012
Wrong operation. Or rather, the Casio is answering:
6/2(2+1)
Which is
6/2(3)
Which is
6/6
Which is
1.
Basically it's answering
Six divided by the result of 2 multiplied by the sum of 2 plus 1.
You're answering six divided by two multiplied by the sum of 2 plus 1.
It's a notation problem.

11/08/2012 4:12pm, #202
I also think the answer is 9.
6/2*3 == 6*2^1*3 =/= 6*(2*3)^1 == 6/(2*3)
/ and * have the same operation priority and we comptute from left to right, no?
(button in upper right corner) Settings> (left menu under My Account) General Settings > in Thread Display Options > Number of Posts to Show Per Page: 40

11/08/2012 4:12pm, #203

11/08/2012 4:16pm, #2041
http://en.wikipedia.org/wiki/Order_of_operations
...In the United States the acronym PEMDAS is common. It stands for Parentheses, Exponents, Multiplication, Division, Addition, Subtraction. Canada uses BEDMAS and the UK uses BIDMAS or BODMAS. In Canada and other English speaking countries, Parentheses may be called Brackets, or symbols of inclusion and Exponentiation may be called either Indices, Powers or Orders, which have the same precedence as Roots or Radicals. Since multiplication and division are of equal precedence, M and D are often interchanged, leading to such acronyms as BOMDAS.
Similarly, there can be ambiguity in the use of the slash ('/') symbol in expressions such as 1/2x. If one rewrites this expression as 1 ÷ 2 × x and then interprets the division symbol as indicating multiplication by the reciprocal, this becomes
Hence, with this interpretation we have that 1/2x is equal to (1/2)x, and not 1/(2x). However, there are examples, including in published literature, where implied multiplication is interpreted as having higher precedence than division, so that 1/2x equals 1/(2x), not (1/2)x.Last edited by Tranquil Suit; 11/08/2012 4:19pm at .
(button in upper right corner) Settings> (left menu under My Account) General Settings > in Thread Display Options > Number of Posts to Show Per Page: 40

11/08/2012 4:23pm, #2051
Thank you!
I knew I was forgetting something in the order of operations!
PEMDAS itself is simple enough to remember (havent thought about it in YEARS) but there's always those deceptively "easy" problems like this one designed to catch people who rush through their work. (An old academic weakness of mine that took a LOT of discipline to beat in school.)
My mistake was doing the division of 6/2 before multiplying the 2(3). Classic quiz trick to see if the student is realy paying atention.

11/08/2012 4:27pm, #206
Except you were right (cuz I sed so, and I should know, I'm an expert at multiplying 2 with 3)
PEMDAS
splits in
P
E
MD
AS
(button in upper right corner) Settings> (left menu under My Account) General Settings > in Thread Display Options > Number of Posts to Show Per Page: 40

11/08/2012 4:33pm, #207
I see what you mean. With the division and multiplication priority being interchangeable depending on which country you learn math in the real fault is in how the problem itself is presented.
solve for "x": 2(2+1)/6 = x
Makes more sense and won't produce "correct errors".Last edited by Mr. Machette; 11/08/2012 4:38pm at .

11/08/2012 4:41pm, #2081
No, they have the same priority. So followup question is in what order do we compute operations of same priority, it is agreed to do it left to right, cause we write from left to right (suck it, Jews).
Here's another bullshit question:
16/8/2 = ?
Basically, which division do you do first?
from same wiki page:
An expression like 1/2x is interpreted as 1/(2x) by TI82, but as (1/2)x by TI83.[8] While the first interpretation may be expected by some users, only the latter is in agreement with the standard rule that multiplication and division are of equal precedence, so 1/2x is read one divided by two and the answer multiplied by x.
When the user is unsure how a calculator will interpret an expression, it is a good idea to use parentheses so there is no ambiguity.
Say what you want about Wiki. Superficial information is done pretty well.Last edited by Tranquil Suit; 11/08/2012 4:47pm at .
(button in upper right corner) Settings> (left menu under My Account) General Settings > in Thread Display Options > Number of Posts to Show Per Page: 40

11/08/2012 4:45pm, #209
Huh both my Ti89 and wolframAlpha say the answer is 9
http://www.wolframalpha.com/input/?i=6%2F2*%282%2B1%29
I am willing to admit I very well may be wrong

11/08/2012 4:54pm, #210
Bookmarks