complex number problem (1 Viewer)

[AGB]

i know that this is a really easy question, but i just dont get it...

find all solutions to z^4 = -1

can someone please explain this to me??

 

[Xayma]

There will be 4 complex roots for z⁴=-1, it wants you to find these. Convert -1 into mod-arg form and then use the roots of complex number thingymagig.

 

[abdooooo!!!]

wasn't this ask in some other thread some time ago: http://www.boredofstudies.org/community/showthread.php?s=&threadid=22712

z⁴ =-1

(z²)² = -1

hence, (z²) = +/- i

but we know that z² = i, will give us this +/- (sqrt0.5 + sqrt0.5*i)

and futhermore, z² = -i will give you this +/- (sqrt0.5 - sqrt0.5*i)

so the answer would be +/- (sqrt0.5 - sqrt0.5*i) and +/- (sqrt0.5 + sqrt0.5*i).

 

[abdooooo!!!]

what?

mod is always positive ie r=1

so arg must equals to -1, hence the theta must be pi.

then you solve it from there if you want to use the mod-arg method. but i reckon this question is quicker by the way i did it.

 

[Xayma]

Yeah I should of done it as a reducable to quadratics but I havent touched complex numbers in ages, not for a term or so...

 

[Giant Lobster]

Xayma stop trying, you don't do ext2

 

[abdooooo!!!]

what the hell... why are people always deleting their posts... makes me look like im talking to myself again. LOL

Originally posted by Giant Lobster
Xayma stop trying, you don't do ext2

do you reckon Xayma is gonna top 3u? hahaha... his got a good chance.

 

[AGB]

Originally posted by abdooooo!!!
what the hell... why are people always deleting their posts... makes me look like im talking to myself again. LOL

do you reckon Xayma is gonna top 3u? hahaha... his got a good chance.

mine didnt make sense, and i didnt wanna look like a fool

 

[abdooooo!!!]

Originally posted by AGB
mine didnt make sense, and i didnt wanna look like a fool

ahaha... yeah delete the thread. what kind of question is z^4 = -1? even people like Xayma who doesn't even do 4u can do it with ease...

 

[xiao1985]

Originally posted by AGB
mine didnt make sense, and i didnt wanna look like a fool

reckon ey... may be bos should make it so dat aprt from modz, or adminz, no one can delete the posts...

 

[abdooooo!!!]

but AGB is a mod... not the mod-arg type... moderator

but it'll be good if they did that. so the buchanan guy would not make me look like a fool everytime i respond to his post. i wonder why he deletes all his posts, maybe he doesn't want sami and other teachers to read it... ahaha you chicken buchanan

 

[Xayma]

Originally posted by abdooooo!!!
do you reckon Xayma is gonna top 3u? hahaha... his got a good chance.

Not a chance, and if I did I would crack and start killing people when I realise that most 4U students still get a higher aggregate from it than me.

 

[:: ck ::]

then y dont u do 4u xayma~~ !?

 

[abdooooo!!!]

Xayma couldn't be bothered cause he thinks he is too superior for the lowly 4u course

hey Xayma, what higher aggregate? if they (us) get a higher aggregate its because you performed bad in other subjects, if you were to score near perfect marks for math you would get 150 scaled marks for 2/3u course.

seriously man you got a good chance... its a 50/50 depending luck... unless there is some other idiot like you who choose not to do 4u for some weird reason.

 

[Xayma]

lol but I would have to top the 3U exam and then I would only get 50 from it and that includes beating all 4U people.

I would have to do it via correspondance, and that would be very hard and Ill end up covering it in Uni anyway.

 

[abdooooo!!!]

Originally posted by Xayma
lol but I would have to top the 3U exam and then I would only get 50 from it and that includes beating all 4U people.

im still not convinced if that is true. my understanding is that the student who did 2/3u that got the heighest mark will automatically top 3u even though 3/4u students got a higher mark. but buchanan said the girl from his school who topped 3u also sat for the 4u exam... umm... i wonder why she is not even in the top 10 of 4u.

if buchanan is not lying then... it should be easy to top 2u then. since by that any student can top 2u even though some cheated by doing 3u. now Xayma go practise heaps of 2u paper now so you don't make any silly mistakes... i'll be looking for you're name at the bos website at the end this year... or at least on the top 20 or 10 in the state.

 

[AGB]

mate, there is this guy at my school who is like 15 and he is in my year (he did ipt when he was 13 and got a band 6)...he didnt wanna do 4u maths coz he reckoned he could just get close to 100% for 2u and 3u

he is seriously a genius....so u got sum competition xayma

 

[Xayma]

Abdooo, the only difference between a student doing Ext 1 and Ext 2 with respect to the 3U exam is that for the Ext 2 student it counts for 2 units, for the Ext 1 student only 1 exam.

AGB I would have done Ext 2 if I had a class to do it with, or even just a teacher but by correspondance it would of been alot harder. Being 16 at uni would suck, you cant hit the piss or anything and you would have to go to one close to you. Hmm competition *Xayma goes and gets someone to knock him off

 

[abdooooo!!!]

Originally posted by Xayma
Abdooo, the only difference between a student doing Ext 1 and Ext 2 with respect to the 3U exam is that for the Ext 2 student it counts for 2 units, for the Ext 1 student only 1 exam.

who doesn't know that... im talking about state topping here.

all im saying is that you are unlikely to top 3u if 4u student is allowed to top it. but then again if that applies to 2u then... hahaha... you are nearly there.... top of the state of mathematics.

Originally posted by AGB
mate, there is this guy at my school who is like 15 and he is in my year (he did ipt when he was 13 and got a band 6)...he didnt wanna do 4u maths coz he reckoned he could just get close to 100% for 2u and 3u

he is seriously a genius....so u got sum competition xayma

a weird genius who doesn't want to do 4u because he is not confident of topping it yet. i reckon he should of accelerated in general math when he was 13 and topping it, then do 2/3u now and top them, next year do 4u and top it as well... so he gets his name on everything... hahaha.

imagine we all started doing 4u at year7... hahaha... and after 4 or 5 repeats even idiots can score 80 or 90% easily.

edit: hey AGB... you go to knox right? is it really easy to get accelerated in your school, do they like force you? i mean there is like so many accelerant from knox.

 

[Xayma]

Originally posted by AGB
mate, there is this guy at my school who is like 15 and he is in my year (he did ipt when he was 13 and got a band 6)...he didnt wanna do 4u maths coz he reckoned he could just get close to 100% for 2u and 3u

Why the hell wouldnt you do 4U then, if you are going to get near 100% in 3U you may as well get 2 units of it counting and then get a resonable score in 4U and you would of beat what you got in 2 and 3U exams.