"YBM" <ybmess@nooos.fr> wrote in message
news:40d9c10a$0$19025$636a15ce@news.free.fr...
| Androcles a écrit :
| > x = -3 or 3
| > y = -4 or 4
| > z = -5, given.
| > z = sqrt(x^2+y^2) - Pythagoras.
|
| Pythagoras ? Where did you see a triangle with sides
| measuring -3, -4 and -5 recently ?

Sure. I put a rule on the hypotenuse and read it from 5 to zero.
That's a negative distance, -5. It would be a positive distance if I read it
from 0 to 5.

| Do you know what
| properties any kind of *distance* has ?

Sure do.

|
| > "This way sqrt is ALWAYS positive."-Dinky the Deranged.
| > So, according to Dinky, z = 5.
| > Egads, Pythagoras was wrong.
|
| z = 5 = sqrt( (-3)^2 + (-4)^2 )
| z = 5 = sqrt ( 3^2 + 4^2 )
| z = 5 = sqrt( (-3)^2 + 4^2 )
| z = 5 = sqrt ( 3^2 + (-4)^2 )
|
| Is any of these equations wrong ?

Yep. I said z = -5, GIVEN.
Since (-5)^2 = x^2 +y^2 for the values of x I gave, ALL of your equations
are wrong. The correct answer is
z = -5 = sqrt( (-3)^2 + (-4)^2 )
z = -5 = sqrt ( 3^2 + 4^2 )
z = -5 = sqrt( (-3)^2 + 4^2 )
z = -5 = sqrt ( 3^2 + (-4)^2 )
 or as the moron Dinky the Deranged said,
"Let x^2 = 5
     then
         x = sqrt(5)     or     x = -sqrt(5)" -Dinky the Deranged.

The variable 'x' can have any value, positive or negative, and it doesn't
need a minus sign. If x = -1, then -(x) = 1.
Similarly, sqrt() doesn't need a minus sign. It has two possible values.
Often there is insufficient data to determine which, but since I *TOLD* you
z = -5, ALL of your equations are wrong, moron. Learn to read.

| BTW, Pythagore says : any triangle with sides 3,4,5 is rectangle
| since 5^2 = 3^2 + 4^2
|
| So Dirk Van de moortel is right, Pythagoras is right too, the only
| one to be wrong here is Androcleps.

I told you z = -5.
I did NOT say -z = -5.
Yet you deny the value I gave you and change it to +5. You are clearly an
idiot who cannot read.

|
|
| > | Anyway, this is a soooo obvious, trivial, evident point that I wonder
| > | what could convince you... Perhaps computing something like :
| > | sqrt(x^2) - ( if(x>0) { x } else { -x } )
| > | on a spreadsheet for one thousand positive and negative values of x
| > | would do it ?
| >
| > "conditionalsimplification"
| > is written into that link.
|
| So what ?

So you cannot read. z = -5, GIVEN.

|
| > It explains how to manipulate the algebra conditionally, it does not imply
| > "This way sqrt is ALWAYS positive."-Dinky the Deranged,
|
| It does, but it would involve at least three lines of trivial logic and
| arithmetic you couldn't understand. You could ask any 12 years old kid
| to show it to you (if you wait for him/her to stop laughing first).

Only if he were as stupid as you and deny what was given in the first place.
Androcles