When there are two or more solutions, do you use OR or AND? (1 Viewer)

[sinophile]

E.g solve (x-2)(x+4)=0

Would you say

The answers are 2 AND -4

or

The answers are 2 OR -4

 

[dp624]

Or

 

[iNerd]

x= 2, -4

 

[sinophile]

Or

oh fuck ive been using AND for two years

 

[MC Squidge]

"or", or "," but i dont think it matters if u use and

 

[dp624]

some people can get really anal when you use AND
e.g
sinx=1
x= blah AND blah

that's wrong

 

[wixxy2348]

I always used to put a ","

 

[axlenatore]

dont use or, that infers that only one of them is an answer, its best just to use at ","

ie (x+2)(x+1) = 0

x = -2,-1

or sin x = 0.5 for 0<x<pi

x = pi/6, 5pi/6

 

[jet]

I say or. My maths teacher was really really anal when he was telling me this as an aside.
(x - 2)(x + 4) = 0
x = 2 OR x = -4

 

[Trebla]

Use your common sense, if you say x = a AND x = b, you are sort of implying that they simultaneously hold, which is impossible.
e.g.
(x + 1)(x - 2) = 0
x = - 1 OR x = 2 (because the x can take EITHER one (not both) of -1 or 2)

It's not technically correct to say x = - 1 AND x = 2 because you're kind of saying x = - 1 and x = 2 at the same time, i.e. - 1 = 2 which is clearly false.

The use of AND/OR here is analogous to its use in probability. When events X AND Y occur, they occur together. When events X OR Y occur, it is either one of event X or event Y only (never both together).

 

[Drongoski]

Use your common sense, if you say x = a AND x = b, you are sort of implying that they simultaneously hold, which is impossible.
e.g.
(x + 1)(x - 2) = 0
x = - 1 OR x = 2 (because the x can take EITHER one (not both) of -1 or 2)

It's not technically correct to say x = - 1 AND x = 2 because you're kind of saying x = - 1 and x = 2 at the same time, i.e. - 1 = 2 which is clearly false.

The use of AND/OR here is analogous to its use in probability. When events X AND Y occur, they occur together. When events X OR Y occur, it is either one of event X or event Y only (never both together).

Trebla

I think this is not strictly correct. When A x B = 0, this can be as a result of only A = 0, only B=0 or both A= 0 and B=0. So the 'OR' should be the inclusive OR. So it can be both.

 

[dp624]

But there are two variables in this case.
Perhaps using AND/OR would be pretty good xD

 

[annabackwards]

But there are two variables in this case.
Perhaps using AND/OR would be pretty good xD

LOL.

I just use "or". I haven't had any problems with using that either... never seen anyone use "and" though.

 

[kwabon]

just use "OR" or ",". preferably, i use the "," , looks cooler.

 

[Trebla]

Trebla

I think this is not strictly correct. When A x B = 0, this can be as a result of only A = 0, only B=0 or both A= 0 and B=0. So the 'OR' should be the inclusive OR. So it can be both.

Well that's a general example when A and B are both zero. But what I'm saying is that in solving the quadratic equation both factors cannot be zero at the same time.
e.g. (x + 1)(x - 2) = 0
There is no way that x + 1 = 0 and x - 2 = 0 together for the same value of x.

 

[Drongoski]

Well that's a general example when A and B are both zero. But what I'm saying is that in solving the quadratic equation both factors cannot be zero at the same time.
e.g. (x + 1)(x - 2) = 0
There is no way that x + 1 = 0 and x - 2 = 0 together for the same value of x.

You've got a point.

 

[nerdsforever]

just use the comma

 

[Drongoski]

just use the comma

This approach is to sidestep the issue.

But really it doen't matter. No one will mark u wrong whichever of the 3 ways u use.

 

[red-butterfly]

just use or...

 

[AnandDNA]

just use ',' to be on the safe side and not need to run this detailed debate through your head during exams