Math question: Help me out... ;)

[Tipmoose]

Is the answer -4 or 4?

[Gatorbait2784]

4 It's been awhile but if I remember right any square of any number is always positive

[Swamplizard]

-4

[jhenderson251]

If there are no parentheses containing the "-" sign, i.e.

(-2)² = ?

I would think the answer is -4

[FoxGator]

-2 ** 2 =
-2 * -2 =
(2 * -1) * (2 * -1) =
(2 * 2) * (-1 * -1) = (Negative one times x changes the sign of x)
4 * 1 = 4

[G8RBrave]

Huh? -2 squared would be -2X-2. Negative times negative is positive.

4 should be the answer, right? What am I missing here?

[G8RBrave]

But, just to be safe:

-2X-2= Tim Tebow

[g8tr96]

Originally Posted by G8RBrave

Huh? -2 squared would be -2X-2. Negative times negative is positive.

4 should be the answer, right? What am I missing here?

You sir are correct.

[Tipmoose]

Which takes precedence? The exponent or the negation?


Is it (-1)(2*2)? or is it (-2*-2)?

[regurgigator]

Originally Posted by G8RBrave

Huh? -2 squared would be -2X-2. Negative times negative is positive.

4 should be the answer, right? What am I missing here?

I'll second that.


Taking it further: -2 to the 3rd power = -2x-2x-2 = -8

-2 to the 4th power = -2x-2x-2x-2 = +16

and so on....

[G8RBrave]

Originally Posted by Tipmoose

Which takes precedence? The exponent or the negation?


Is it (-1)(2*2)? or is it (-2*-2)?

Ok, I see where the discrepancy in answers is coming from now.

I'm still going with 4.

[g8rman95]

Your second scenario is correct Tip.

[rburnett]

PEMDAS... E comes way before S.. its 2 squared... then negative = -4

[GatorPJ]

The answer is -4.

Think of it this way - any number minus itself has to be equal to zero:

2^2 - 2^2 = 0

4 - 4 = 0

The comment about PEMDAS is 100% correct. Just remember an exponent only affects the number or letter immediately to its left unless there are parentheses.

[CCDGator]

I'm with the -4 crowd. Square 2 and negate the result.

If you really mean the square of -2, use parentheses.

Think of how we interpret an expression like -x^2. We mean square x and negate it.

Likewise: (a - b)(a + b) = a^2 - b^2 (i.e. the square of a minus the square of b).

[g8tr93]

An exponent just implies mutliplying the number by itself as many times the exponent indicates. Thus -2^2 is in fact -2 X -2 which is 4. I teach math at the elementary school level and am 100% sure this is correct. Unless there's a new math I haven't heard about.

[regurgigator]

Originally Posted by rburnett

PEMDAS... E comes way before S.. its 2 squared... then negative = -4

I guess you learn something new everyday!

As a 50-year old civil engineer (we do a fair amount of math), I'd never heard of PEMDAS. In Wikipedia's entry regarding PEMDAS (order of operations), the example is given of:

-3 squared = -(3 squared) = -9

Go figure...

[CharlestonGator]

This is it--I think Brave has it right:

-2 x -2

Multiplying a negative with a negative changes it to a positive.

4 is the answer

[g8tr96]

I was wrong.

Here is the real answer......I think.

-(2 squared) = -4

[G8RBrave]

I really think it depends on who is writing the problem, too. I see what rburnett is saying about PEDMAS. I think we were always taught that the parentheses were implied, that's why my initial reaction was that it was 4 rather than -4.

I do think in a very strict sense the answer is -4 now that I think about it.