Basic Math Problem - Need Help

[benbo]

sin(X + Y) = sinx + y ?

sin(0+0) = sin0 + 0 = 0 + 0 = 0 = sin(0).

That proves it, right?



I may have located a technical explanation -

http://www.schooltube.com/video/efb63be016b142e4a64c/

 

[MA_PE]

I say 9. I'm old

 

[benbo]

Let's hold a poll. THat's the best way to solve math problems.

 

[ptatohed]

I think the answer is 9. Parenthesis and then left to right. This assumes the "/" means division and we also have to assume implied multiplication using the parenthesis. These are fair assumptions.

If the "/" is a fraction bar, then the answer is still 9 if we assume the 6 is the numerator and the 2 is the denominator.

If the "/" is a fraction bar, the answer can only be 1 if we assume the 6 is the numerator and the 2(1+2) is the denominator but I don't think that's the fairest assumption.

I say 9.

 

[csb]

Sap-i learned PEMDAS...you don't have the parentheses.

That's how I got nine.

Now where's the SOH CAH TOA problem so I can use all my math chants?

 

[Ble_PE]

Sap-i learned PEMDAS...you don't have the parentheses.

That's how I got nine.

Now where's the SOH CAH TOA problem so I can use all my math chants?

Same here.

 

[Capt Worley PE]

Never mind the reason why, just invert and multiply!

 

[Master slacker]

^^^ This ain't sex ed.

 

[Capt Worley PE]

I had a vector calc professor that would be halfway through a proof and write, "BAOG," then the final equation. When asked about it, he said, "By act of God. I know you people don't really care how we got there."

 

[mizzoueng]

What if you were using a calculator, on a plane, on a treadmill, to solve this equation, would that affect the answer?

Side question, when is it appropriate to use affect over effect?

 

[civengPE]

I am of the opinion that it can be both, because it is just a poorly written equation. It can be interpreted two different ways:

6

---------------

2(1+2)

Or

6

----- (1+2)

2

I would ASSUME that if the intention was for case 1 then the equation should have been 6/(2(1+2)). But the argument could be made that case 2 should be written as (6/2)(1+2).

So my answer is <10. ;-)

Edit: Why does the board remove the spaces in my post?

 

[mudpuppy]

Edit: Why does the board remove the spaces in my post?

That's normal HTML behavior. HTML don't allow extra spaces. Use a Code Box to preserve them:


6

---------------

2(1+2)

Or

6

----- (1+2)

2

 

[ptatohed]

I am of the opinion that it can be both, because it is just a poorly written equation. It can be interpreted two different ways:

6

---------------

2(1+2)

Or

6

----- (1+2)

2

Actually, not so. As written, it can only be interpreted one way. The answer has to be 9, as written.

 

[Supe]

Unsurprisingly, I agree with 9, my coworker who grew up with a TI-34234091 platinum edition says its 1.

I think most people are just so used to hearing PEMDAS, they forget that this is how it works:

http://www.factmonster.com/ipka/A0933340.html

When I rewrote the problem for him as 6*(1/2)(1+2) it blew his mind...

 

[Capt Worley PE]

When I rewrote the problem for him as 6*(1/2)(1+2) it blew his mind...

 

[mudpuppy]

I know it is hard for engineers to accept, especially considering math is the foundation of science, a subject we've been taught always give a concrete, factual answer, but there is no correct answer to this. But it does teach the lesson that you should always communicate your thoughts clearly.

 

[Capt Worley PE]

But it does teach the lesson that you should always communicate your thoughts clearly.

True dat.

 

[MA_PE]

Made me think of this.

Three Stooges "Dizzy Pilots"

(Moe sees Curly sawing the plane's wings instead of the hanger doors. He quickly stope him.)

Moe: Hey, you nitwit! Don't saw the wings, you saw the garage!

Curly: I see the garage, but I don't saw the garage. You are speaking incorrectly. You are murdering the King's English! Et cetera.

 

[ptatohed]

I know it is hard for engineers to accept, especially considering math is the foundation of science, a subject we've been taught always give a concrete, factual answer, but there is no correct answer to this. But it does teach the lesson that you should always communicate your thoughts clearly.

mp, I respectfully disagree. If the rules of operations are applied correctly, there is only one answer to the original equation (answer = 9). There are several videos on youtube about this (even videos "proving" the answer is 1) but this video is pretty good (in favor of 9).

.

Yes, I agree, all math problems should be written so as to avoid any ambiguity (although, this thread would have been a lot more boring if the equation had been written as "(6/2)(1+2)" ).

 

[mudpuppy]

Order of operations is not a mathematical theory that can be proven, it is a mutually agreed-upon set of rules that create a method of communication. Just like any other language there are times it can be interpreted in different ways. Sometimes, like in poetry, this is encouraged. In the language of math, it's very much discouraged. What we have here is people taking advantage in a weakness of the clarity of our current system of order of operations in order to create arguments. I think this is a good thing when it gets people thinking about the problem and how to avoid it. But to try to prove they're right is futile.