Mathematics
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OpenStudy (anonymous):
can anybody solve this : if 1,a1,a2....a(n-1) are nth roots of unity,then the value of (1-a1) (1-a2)(1-a3)...(1-a(n-)) is equal to ?
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OpenStudy (anonymous):
Hello, @Reeti1 :)
OpenStudy (anonymous):
(:
OpenStudy (anonymous):
HI
OpenStudy (anonymous):
What's up?
OpenStudy (anonymous):
NM ! YOU SAY ?
your asl ?
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OpenStudy (anonymous):
14
I'm a boy
England
Now, let's get started on this question :)
OpenStudy (anonymous):
ahh this is 12th grade mathematics dude ;)
OpenStudy (anonymous):
Well, if you say so :3
OpenStudy (anonymous):
can you solve it ?
OpenStudy (anonymous):
Of course I can :P
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OpenStudy (anonymous):
plaese move then
OpenStudy (anonymous):
Moving...
OpenStudy (anonymous):
move on*
OpenStudy (anonymous):
Okay, all the nth roots of unity are roots of this polynomial...
\[\huge x^n - 1 = 0\]
OpenStudy (anonymous):
OKAY
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OpenStudy (anonymous):
Consequently, this polynomial is equal to...
\[\LARGE (x-1)(x-a_1)(x-a_2)...(x-a_{n-1})=0\]
OpenStudy (anonymous):
But also
\[\LARGE x^n - 1 = (x-1)(x^{n-1}+x^{n-2}+...x+1)\]
OpenStudy (anonymous):
Sorry
\[\Large (x-a_1)(x-a_2)...(x-a_{n-1})=x^{n-1}+x^{n-2}+...x+1\]
OpenStudy (anonymous):
Is everything clear? @Reeti1
OpenStudy (anonymous):
the choices are :
a. 1
b. 1/2
c. n
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OpenStudy (anonymous):
Yeah yeah... but everything is clear to you so far?
How we arrived at this...
\[\Large (x-a_1)(x-a_2)...(x-a_{n-1})=x^{n-1}+x^{n-2}+...x+1\]
OpenStudy (anonymous):
answer is n i guess
OpenStudy (anonymous):
YES!
See?
Just replace x with 1
\[\Large (1-a_1)(1-a_2)...(1-a_{n-1})=1^{n-1}+1^{n-2}+...1+1\]
OpenStudy (anonymous):
And you get n 1's that you'll add to get... n
haha
did I solve it or what? ^.^
OpenStudy (anonymous):
you did it ! but wow how ?
you're just 14
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OpenStudy (anonymous):
I'm actually well over 200?
^.^
@dmezzullo already said on chat... age doesn't matter XD
OpenStudy (anonymous):
thank you :)
OpenStudy (anonymous):
;)
OpenStudy (anonymous):
ok one more
OpenStudy (anonymous):
Let's go :)
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OpenStudy (anonymous):
cube root of i is equal to ?
OpenStudy (anonymous):
cube root of i?
:(
\[\huge \sqrt[3]i\]
OpenStudy (anonymous):
yep
OpenStudy (anonymous):
is that even possible? :/
OpenStudy (anonymous):
haha of course it is :D
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OpenStudy (anonymous):
First, put i in polar form ^.^
OpenStudy (anonymous):
okay done