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I come from brazil and for me -2^2 should be -2 times -2 = +4 In US this is -4. I am telecommunication engineer and know about math. Is this real right?

Guest Aug 19, 2015

Best Answer 

 #7
avatar+90996 
+5

Here is a good reason why  $$-3^2$$   should (and does) equal -9  NOT    +9

On its own it seems illogical, I will agree with you BUT what about

 

$$8-3^2$$      now if   $$-3^2=+9$$     

 

then that would mean that       $$8-3^2$$ = $$8+3^2$$

 

Now I expect you would agree  

 $$8-3^2=8-9=-1$$                    and

$$8+3^2=8+9=17$$

 

So using this logic   $$-3^2$$       cannot equal      $$+3^2$$

 

So       $$-3^2=-1*3^2=-9$$

 

I am from Australia and we do this this way here too.  :)

Melody  Aug 20, 2015
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12+0 Answers

 #1
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0

You are right! -2 x -2=+4 in every country including the US. Where have you seen it as -4 in the US?

Guest Aug 19, 2015
 #2
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0

@ my daughter high school they say for example -2^4 is -2 * 2 * 2 * 2.

Even on google if you type calc and add -2 xy 4 it will be -16.

this is really weird  to me

Guest Aug 19, 2015
 #4
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0

Don't rely on Google Calculator on the Web, because it's designed by young people and they often make mistakes. I would never use it reliably. Use a good calculator such as HP Scientific calculator. You will see that the answer is 16 not -16.

Guest Aug 19, 2015
 #5
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0

are you teacher?

Guest Aug 20, 2015
 #6
avatar+26326 
+5

(-2)^2 = 4  but -2^2 = -4 because exponentiation (raising to a power) takes a higher priority than negation.  Any good scientific calculator should do this.

Alan  Aug 20, 2015
 #7
avatar+90996 
+5
Best Answer

Here is a good reason why  $$-3^2$$   should (and does) equal -9  NOT    +9

On its own it seems illogical, I will agree with you BUT what about

 

$$8-3^2$$      now if   $$-3^2=+9$$     

 

then that would mean that       $$8-3^2$$ = $$8+3^2$$

 

Now I expect you would agree  

 $$8-3^2=8-9=-1$$                    and

$$8+3^2=8+9=17$$

 

So using this logic   $$-3^2$$       cannot equal      $$+3^2$$

 

So       $$-3^2=-1*3^2=-9$$

 

I am from Australia and we do this this way here too.  :)

Melody  Aug 20, 2015
 #8
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0

Melody: Your logic is srewy! I think you spend too much time on the beach!. A negative integer raised to a positive EVEN integer is ALWAYS positive. A negative integer raised to an ODD positive integer is ALWAYS negative. Case closed.

Guest Aug 20, 2015
 #9
avatar+90996 
0

Well it seems you are the expert anon, :))

Do you do your own brain surgery too?

Melody  Aug 20, 2015
 #10
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0

Lets thin about just my original question: how much is -2^2 if you think in a line (negatives - left side and positive right side from 0). You cannot separate the negative signal from 2. So -2^2 it is the -2 (a point) power 2. It should result on +4 i am really confused about those methods on US and Australia.

Guest Aug 20, 2015
 #11
avatar+2 
0

$$Melody
I agree with you 8 - 3^2 = 8 - 9 = -1
but my question is how much is -2^2

to me should be +4$$

heron  Aug 20, 2015
 #12
avatar+1311 
0

Well Alan and Melody explain it to you so now all you have to do is change your mind. That is easer than changing all the math rules.

 

I figure out that Santa Clause is not real when I was 6. Even though I think he was real that not make it true. My little sister figured it out but she keep changing her mind because she not want to hurt his feelings if he is real. Hahaha She probably make up her mind before she is 8.

 

If you want to use Latex to write things on here then you should learn how to do that too. Mathgod know how to use it and he is 12. He know how to do math better than you too.

 

$${$No one is impressed by b******t on here }\\
{This is how it should look } \\\\
{Melody I agree with you 8 - 3^2 = 8 - 9 = -1 ${ but my question is how much is } -2^2 ${ to me should be +4}$$

Dragonlance  Aug 20, 2015
 #13
avatar+90996 
0

Now Dragonlance,

Your opening sentence was good but you do not need to get rude with people.

 

Anon, I think it is great that you had a go at LaTex.  I am always trying to encourage people to use it and you cannot learn it all at once :)

So please keep up your great efforts   

 

 

There are a lot of ways to put spaces between words.

 

 

Dragonlance has done it with this code:

{$This is how it should look }

$${$This is how it should look }$$

 

 

I have never used code exactly the same as Dragonlance's.

I may have used \mbox{This is how it should look }

$$\mbox{This is how it should look }$$

\ says a function is following and mbox stands for messsage box :)

 

 

Here is another way

This\; is \;how\; it\; should\; look

$$This\; is \;how\; it\; should\; look$$

Melody  Aug 21, 2015

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