Yeah, blah blah, home alone because I'm sick, math homework, can't ask my mom what the hell is wrong with this because she doesn't have a clue, dad's at work, and my teacher is kinda, you know, at school where I'm not because I'm sick.

b = 4, a = -1, and x = -5

b^2 + a^2
x

Ok, b^2 is 16. But a^2...I got a few answers. At first I was just doing the problem, came up with +1, no biggie. But judging from the other problems (all 23 of them) (they all came out to whole numbers) 17/-5 didn't look right. So I go to my trusty calculator, and punch in -1^2. Comes up with -1. Then I go with -1*-1 and come up with +1.

What the hell? It's the same thing, -1^2 and -1*-1, isn't it? Show me what's up with this Massassi, please. It's confusing...

You meant (-1)^2.

Basically, -1x-1=1.

OK, what's the difference that makes my calculator give the correct answer that way and it didn't before?

Oh, and does this mean that it was just a poorly written problem in my book?

On a calculator, yes.

It will only square the coefficient, not the negative.

Yep, theres a great difference.

So then on a calculator, it assumes a numerical coefficient of 1 for negative numbers then, and parentheses around it show that it's just -1? OK.

Yeah. Basically, whenever you raise a negative number to a power on a calculator, use parentheses.

Welcome to the world of graphing calculators

[QUOTE=Cool Matty]Welcome to the world of graphing calculators :D[/QUOTE]
Eh?

It's not a poorly writen problem it is quite common accualy but it has
to do with how the calculator accualy processes the information.
It's not smart enough to know what order to do it in all the time so
thats why you need the parentheses

this is why it is importaint to know the math and how the calculator works.

hopefuly if you didn't get it yet this will explain it better:


-1^2 =1

On a calculator you need to enter:

(-1)^2

Other wise it will square the number but not the negative i.e.

it will square the 1 THEN put on the negative.

if you enter:

-1^2

the calculator will accualy solve:

-(1^2) = -1

Be VERY careful, when doing the above.

NOT ALL CALCULATORS ACT THE SAME.

Generally, any calculator with a display that shows what you are punching in (such as the higher-end scientific calculators, and graphing calculators) will need the ().

BUT, many of the low-end scientific calculators, ones without a second line display for what you are punching in, assume when you punch in -1, that you mean (-1).

Always do a test when you are using a new calculator that you are not familiar with:

-1^2 = -1
(-1)^2 = 1

If you get those answers, your calculator does the method above. Otherwise, it assumes -1 means (-1), and you need to be aware of that.

An example of a calculator that does not perform as posted above is Windows' own scientific form calculator. Try it!

The reason it does that is because it works properly.

Calculators are generally (unless they're a load of crap when dealing with complex formulae) programmed to follow BODMAS. That's brackets, of, division, multiplication, addition and subtraction. Anything in brackets is worked out first, then powers, then division and multiplication, then addition and subtraction. So using -1^2 does 1^2, which is one, then 0-1, which is -1. With brackets, it works out 0-1 first, and then squares that.

Alternatively, you could hit -1, equals, then squared, then equals. Or just remember that an even power of any number is always positive.

Of course, don't hit shift before squaring with this method. Although it's a good way of seeing if your magic box can work with complex numbers.

Wait till Zloc comes across imaginary numbers!

Imaginary numbers are fun. Especially in second order differential equations.

yeah, but playing with i can cause all sort of messes :p

Ok, this is a lot simpler if you forget about the calculator crap and remember the VERY SIMPLE CONCEPT THAT A NEGATIVE SQUARED IS POSITIVE

(But yeah, they're right .. in ti83/4 etc if you do -1^2 the order of operations go square, then apply the negative.)

Pommy, I know, I was CHECKING my work. My teacher is anal about that. Use the calculator to check, and check only.