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• View Poll Results: Is -2^2 equal to 4 or -4?
4
53.85%
-4
46.15%

1. There was a thread on this a few days ago and a big discussion but I didn't understand what the actual answer was. Is -2^2 equal to 4 or -4? I've made a poll for you people to vote.

Personally I think it's 4 since a square is always positive but there were some crazy people who said it was -4. What do others think?

Also my friend told me that 0.999...=1. I'm not sure if he was joking since there's always a really really small difference between the approximations and 1. I'm pretty sure it's not true but can anyone confirm it?
2. because you haven't put any brackets in there it is -4!
(-2)^2 = 4

edit: the 0.9 recurring could be considered to be 1 for ease but it is technically not!
3. 0.9* (the star equals recurring) does equal 1 in theory.

It depends on the context.

(-2)^2 = 4
-(2^2)=4
-2^2 can be either.
4. It's -4 if you read it as -(2^2), or 4 if you read it as (-2)^2. If you were to read it following the rules of which sign you read first,* it would be -4 as you always perform index operations (like squaring or cubing) before anything else (unless it's in a bracket).

Edit: *Ah, BODMAS. I remember... I never forgot... I'm sleep deprived ok!?
5. Oh my god.

-2^2 is -4. BODMAS will tell you this, because -2^2 means "square the 2, then put a - in front of it". (-2)^2 is +4, because two minuses will cancel. It's notation. It's not open to debate - unless you put those brackets in, writing "-2^2" means "-(2^2)" by default.

And yes, 0.999... = 1. The typical argument against this goes something like "yeah, but, there's a difference of 0.000...(infinitely many)...001 between them", but there's no such thing as infinitely many zeroes and then a 1 at the end.

6. (Original post by studentbug)
There was a thread on this a few days ago and a big discussion but I didn't understand what the actual answer was. Is -2^2 equal to 4 or -4? I've made a poll for you people to vote.

Personally I think it's 4 since a square is always positive but there were some crazy people who said it was -4. What do others think?

Also my friend told me that 0.999...=1. I'm not sure if he was joking since there's always a really really small difference between the approximations and 1. I'm pretty sure it's not true but can anyone confirm it?
. It's true
7. With Brackets = 4
Without = -4
8. aka [/latex] (-2)^2 = 4[/latex], because the two minuses cancel each other out.

Verbally, it depends on how you say it. If you pause after minus 2 (minus two, squared) then that implies that you square the -2, but if you say it all together (minustwosquared) or pause after the minus (minus *pause* two squared), then you square the two and make the resultant answer negative.
9. (Original post by generalebriety)
Oh my god.

-2^2 is -4. BODMAS will tell you this, because -2^2 means "square the 2, then put a - in front of it". (-2)^2 is +4, because two minuses will cancel. It's notation. It's not open to debate - unless you put those brackets in, writing "-2^2" means "-(2^2)" by default.

And yes, 0.999... = 1. The typical argument against this goes something like "yeah, but, there's a difference of 0.000...(infinitely many)...001 between them", but there's no such thing as infinitely many zeroes and then a 1 at the end.

yes i agree we leave this. it is a dumb question a 12 year old should be able to answer!
10. (Original post by chr15chr15)
edit: the 0.9 recurring could be considered to be 1 for ease but it is technically not!
Yes it is.
11. Thanks for your opinions - hope I'm not causing any offence!

Surely -2^2 is given by substituting -2 into the graph of x^2? That would say it's 4 I thought. Maybe it's ambiguous?

Why can't you have infinitely many zeros and then a 1? We have imaginary numbers after all.
12. (Original post by RightSaidJames)
[latex[-2 x -2 aka -2^2 = 4[/latex], because the two minuses cancel each other out.
I'm going to start neg repping people if they will continue to spread such utter ********. I've never seen such a bunch of misinformed people in my life. Can one of you just use your brain and a bit of primary school BODMAS-style thinking to get the correct answer of -4 and then accept it, please?
13. (Original post by boy)
. It's true
but 1/9 does not equal 0.111...
i know your gonna come up with some stuff that its infinitely close so we can say it is, but its a fact it isn't!
14. (Original post by studentbug)
Thanks for your opinions - hope I'm not causing any offence!

Surely -2^2 is given by substituting -2 into the graph of x^2? That would say it's 4 I thought. Maybe it's ambiguous?
You're talking about (-2)^2, which is definitely 4. I'm talking about -(2^2), which is definitely -4. I hope we agree this far. The notation -2^2 is not ambiguous - it is universally accepted to mean the latter.

(Original post by studentbug)
Why can't you have infinitely many zeros and then a 1? We have imaginary numbers after all.
Because it doesn't make sense. Imaginary numbers do - you might not be able to hand me -3i apples, but it's mathematically sensible and consistent.
15. (Original post by chr15chr15)
but 1/9 does not equal 0.111...
i know your gonna come up with some stuff that its infinitely close so we can say it is, but its a fact it isn't!
OK (not that the point raised is correct), consider the following series:

.

This is equal to the recurring decimal in question.

Now sum the series to infinity:

.
16. ^^^1/9 is 0.111. Check with your calculator
17. (Original post by chr15chr15)
but 1/9 does not equal 0.111...
i know your gonna come up with some stuff that its infinitely close so we can say it is, but its a fact it isn't!
There's no such thing as "infinitely close". 1 and 0.999... are exactly the same thing.
18. Guys, we had a thread like this the other day, please stop creating them. Generalebriety has explained it well, so I'm closing this before it becomes another 8 page spam-fest.

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