/sci/ - Science & Math

[Anonymous No.10630323]

well

[Anonymous No.10630343]

>>10630323
Sorry /sci/. The thread on /v/ just got deleted, so now it's spilling over into this board, probably because someone is still butthurt.

But while I'm here, I might as well post one thing.

To the guy in the /v/ thread who claimed to be a math tutor and kept posting sideways photos of handwritten solutions,
>How many different ways do I need to solve this to satisfy you?
Nobody asked you to solve the problem again. My post was about your incorrect use of the term "FOIL" and your insistence that replacing numbers with variables makes things easier when it does not.

To reiterate,
>FOIL is just a mnemonic to make you remember to multiply every term. (x+y)(a+b+c) is still considered foiling, as is (x) (a+b(c)).
No, FOIL is a mnemonic device used to teach multiplication of two binomial expressions. It makes no sense to use that mnemonic for a problem like (x)(a + b(c)). What you're describing is not, and should not, be called "foiling". What you're describing is the distributive property of multiplication — or, if you want the verb, you're distributing, not "foiling".
>Just substitute the numbers for variables and you'll see it.
Substitution of numbers for variables doesn't make it easier or harder. Replacing 2 with x doesn't do anything to enable "foiling" as you call it. Maybe your 2nd grade math textbook used variables when teaching distribution but you don't have to get everything into that same form in order to use the same mathematical laws. You can just do it with numbers, which is less convoluted and therefore more easily understood for the children you supposedly tutor.

[Anonymous No.10630353]

>>10630343
/sci/ is like a dozen guys at best. Leave us alone.

[Anonymous No.10630451]

>>10630323
16/2[8-3(4-2)]+1
16/2[8-3(2)]+1
16/2[8-6]+1
16/2[2]+1
16/4+1
4+1
5

[Anonymous No.10630479]

>>10630343
What is FOIL and what did the guy do?

[Anonymous No.10630575]

>>10630451
16/2[8-3(4-2)]+1
16/2[8-3(2)]+1
16/2[8-6]+1
16/2[2]+1
8[2]+1
16+1
17

[Anonymous No.10630647]

>>10630575
Have to get rid of bracket first.

[Anonymous No.10630672]

>>10630451
>16/2[2]+1
>16/4+1

Not sure why you assume 16/2[2] implies 16/(2[2]).

[Orbulon, the Intellectual No.10630688]

17

[Anonymous No.10630703]

>>10630451
this and
>>10630647
this

/thread

[Anonymous No.10630751]

[math]\frac{16}{2[8-3(4-2)]} + 1[/math]
[math]\frac{16}{16-6(8-4)} + 1[/math]
[math]\frac{16}{16-6(4)} + 1[/math]
[math]\frac{16}{16-24} + 1[/math]
[math]\frac{16}{-8} + 1[/math]
[math]-2 + 1[/math]
[math]-1[/math]

[Anonymous No.10630761]

81

[Anonymous No.10630774]

>>10630479
FOIL stands for "first, outer, inner, last" and it's used to teach students how to multiply two binomial expressions, e.g.,

(a + b) * (c + d) = a * c + a * d + b * c + b * d

The words "first, outer, inner, last" refer to the four terms in the expanded expression by their positions in the two binomial expressions that were multiplied.

a * c = "first"
a * d = "outer"
b * c = "inner"
b * d = "last"

See: https://en.wikipedia.org/wiki/FOIL_method

Anyway, as you can see, this is all irrelevant to the order of operations in the problem given in the original post.

The guy in the /v/ thread, who claimed to be a math tutor, wasn't really making a lot of sense. He replaced 2 with the variable x, claiming that this variable substitution made it easier to see how "foiling" gives the correct answer, despite the fact that he wasn't actually using the FOIL method, as he was not multiplying two binomial expressions. He was just distributing the x, really just 2, to the terms inside of the parentheses, per the distributive law. It's also worth noting that he did this prior to the division.

[Anonymous No.10630809]

>>10630451
>>10630647
>>10630703
No. The brackets imply multiplication. Multiplication and division are done together in order from left to right. The correct answer is 17.

[Anonymous No.10630817]

>PEMDAS
>Paranethesis
>Exponents
>Multiplication & Division
>Addition & Subtraction

For clarification, there is no significance between writing multiplication in the form of "*", "x", " ⋅", or implied multiplication (appearing as a coefficient juxtaposed to the term to be multiplied). Therefore, the first division operation will be applied to the first 2, and not the entire resulting term as if it were grouped on the right.
16 / 2 * [8 - 3 * (4 - 2)] + 1
Parentheses are removed after the reduction of terms within their bounds.
16 / 2 * (8 - 3 * 2) + 1
16 / 2 * (8 - 6) + 1
Given that multiplication and division are in the same tier, they will be executed in the order of their appearance from left to right. In this case, division shall be first.
>>10630451 implies that results their parentheses until they have been operated on by an outside value - this makes no sense, as you could have two sides of an equation result in 2 = (2) of which you would have to claim as a false statement. This would be ludicrous. Therefore, the 16 / 2 is performed first rather than 2 * 2.
16 / 2 * 2 + 1
8 * 2 + 1
16 + 1
17

>>10630751
There are not parentheses enclosing "2[8 - 3(4-2)]", and therefore the divisor 16 is only 2.

[Anonymous No.10630848]

16÷2[8-3(4-2)]+1
8[8-3(4-2)]+1
[64-24(32-16)]+1
[64-(768-384)]+1
(64-384)+1
-320+1
-319

[Anonymous No.10630857]

>>10630848
>8*(3(4-2)) = (8*3)*(8*(4-2))
It burns

[Anonymous No.10630860]

>>10630848
lol

[Anonymous No.10630875]

>>10630857
Problem?

[Anonymous No.10630882]

>>10630809
>>10630817
I think these posts are correct, because I have not seen any evidence that implied multiplication (i.e. multiplication by juxtaposition) has higher precedence than division.

Wikipedia's "Order of operations" article says this:
>... in some of the academic literature, multiplication denoted by juxtaposition (also known as implied multiplication) is interpreted as having higher precedence than division, so that 1 ÷ 2x equals 1 ÷ (2x), not (1 ÷ 2)x.
But of course, there's no citation for that sentence, so it's worthless.

In any case, the whole point of OP's image is to bait people into giving the wrong answer because of how badly written it is. We are allowed to use parentheses for clarification even when they are not required, and the expression given by OP is a perfect example of why. Visually, 2[8 - 3(4-2)] looks like one term which would all belong in the denominator if the division were written as a fraction. Anyone not trying to cause confusion would write
>(16 ÷ 2)[8 - 3(4 = 2)] + 1
or, alternatively, would simply not use the fucking obelus (÷) symbol in the same expression as implied multiplication. Even something like
>16 ÷ 2 × [8 - 3(4 = 2)] + 1
would be less ambiguous.

[Anonymous No.10630892]

>>10630817
I think this post is correct, because I have not seen any evidence that implied multiplication (i.e. multiplication by juxtaposition) has higher precedence than division.

Wikipedia's "Order of operations" article says this:
>... in some of the academic literature, multiplication denoted by juxtaposition (also known as implied multiplication) is interpreted as having higher precedence than division, so that 1 ÷ 2x equals 1 ÷ (2x), not (1 ÷ 2)x.
But of course, there's no citation for that sentence, so it's worthless.

In any case, the whole point of OP's image is to bait people into giving the wrong answer because of how badly written it is. We are allowed to use parentheses for clarification even when they are not required, and the expression given by OP is a perfect example of why. Visually, 2[8 − 3(4 − 2)] looks like one term which would all belong in the denominator if the division were written as a fraction. Anyone not trying to cause confusion would write
>(16 ÷ 2)[8 − 3(4 − 2)] + 1
or, alternatively, would simply not use the fucking obelus (÷) symbol in the same expression as implied multiplication. Even something like
>16 ÷ 2 × [8 − 3(4 − 2)] + 1
would be less ambiguous.

[Anonymous No.10630916]

I really hope I didn't screw this up, since I can't check latex on my cell.
[eqn](16 × \frac{1}{2}) × {8-[i1^2(i2^2+2)]3} + 1[/eqn]

[Anonymous No.10630917]

>>10630353
and five hundred /pol/ evangelists.

[Anonymous No.10630923]

>>10630916
Yep, nope lost my tertiary brackets {} in latex.

[Anonymous No.10631060]

>>10630323

[Anonymous No.10631254]

>>10630323
16/2[8-3(2)]+1
16/2[8-6]+1
16/2[2]+1
8[2]+1
16+1
17

[Anonymous No.10631260]

PEMDAS , but when it comes to Multiplication and Division and then addition subtraction you do the calculations from left to right.

Christ you guys have had too much higher math you forgot basic arithmetic.

[Anonymous No.10631261]

How do retards still fall for this bait?
It isn't agreed upon in higher mathematics on whether you do multiplication by juxtaposition or PEMDAS from left to right first
The question is ambiguous
Always use parentheses and fraction notation

[Anonymous No.10631272]

[eqn]16 × \frac{1}{2}[8+\neg{3}(4+\neg{2})]+1[/eqn]
Just swap all division and subtraction to multiplication and addition.