Mathematics
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OpenStudy (anonymous):
If z being a complex number lies on the unit circle and the sum of z with its reciprocal is 1, then find z^235
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OpenStudy (anonymous):
wt bt this??
OpenStudy (amistre64):
z^235? thats alot
OpenStudy (anonymous):
theres no answer given bt frm what i know it comes out to be a simple answer
OpenStudy (amistre64):
z + 1/z = 1?
OpenStudy (anonymous):
yeah
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OpenStudy (amistre64):
z^2 +1
------- = 1; z^2 +1 = z; z^2 -2 +1 = 0
Z
OpenStudy (amistre64):
(z-1)^2; z = 1
OpenStudy (amistre64):
z^235 = 1 then ?
OpenStudy (anonymous):
but z isnt 1, its a complex number...
OpenStudy (amistre64):
typoed it again
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OpenStudy (anonymous):
z is the 3rd root of -1.
because z^2-Z+1=0;
z^3=1
z^235=z=-1+isqrt(3) /2
OpenStudy (amistre64):
z^2+1 = 1
z^2 = 0
z=0 ?
OpenStudy (anonymous):
Z^3=-1
(z+1)(z^2-z+1)=0
Z^2-z+1=0;
OpenStudy (amistre64):
so that means the the complex part is either up or down
OpenStudy (anonymous):
z+1/z=1
z^2-z+1=0.
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OpenStudy (anonymous):
i think dipankars right, did u apply the demoivres theorem??
OpenStudy (anonymous):
no need to apply it....
OpenStudy (amistre64):
dip is usually right ;)
OpenStudy (anonymous):
i have given the steps....
OpenStudy (anonymous):
z is the complex roots of -1.
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OpenStudy (anonymous):
so but then howdu get z^235??
OpenStudy (anonymous):
u must realize amistre m doing wht u often do;)
OpenStudy (amistre64):
guess wildly lol
OpenStudy (anonymous):
z^235=z^234*z=(z^3*78)^z=1*z=z
OpenStudy (anonymous):
no not that...like wht u were doin with the tangent plane question...
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OpenStudy (anonymous):
ok dipankar....
OpenStudy (amistre64):
ahhh... :)
OpenStudy (anonymous):
with all the three ;)
OpenStudy (amistre64):
its good to be smart :)
OpenStudy (anonymous):
him i think u have understood the process...
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OpenStudy (anonymous):
yeah right...
OpenStudy (amistre64):
so, when I find z=0, the complex parts have to be pure imaginaries then right? like "i"
OpenStudy (anonymous):
ill tell u what
OpenStudy (anonymous):
z + 1/z =1
let z=cosθ + isinθ
1/z = cosθ - isinθ
z + 1/z = 2cosθ = 1
cosθ = 1/2
hence z = 1/2 + √3/2
OpenStudy (amistre64):
z^235 = i^235...235/4 = 58 and 3 remaining
i, -1, -1
z^235 = -i?
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OpenStudy (anonymous):
√3/2 x i sorry
OpenStudy (anonymous):
no man
look above
z = 1/2 + i√3/2
OpenStudy (amistre64):
lol...stab in the dark then :) i see what you did
OpenStudy (anonymous):
now du wanna know the other one as well?
OpenStudy (amistre64):
i do, but at this late hour it aint gonna stick to well ;)
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OpenStudy (anonymous):
hahaha...wts d time there??