Q. 25444 (another solution)
z^ +1 =iz^2 +∣z∣^2
let z=x+iy , ⇒
x−iy+1=i(x^2 −y^2 )−2xy+x^2 +y^2
or (x−y)^2 =x+1 ,and
(y^2 −x^2 )=y
let y−x=u and y+x=v
⇒ 2u^2 =v−u+2 ...(i)
2uv=u+v ....(ii)
⇒ v=(u/(2u−1)) , substituting in (i)
2u^2 +u=(u/(2u−1))+2
u=1 satisfies this , so
⇒ (2u+3)(u−1)=(u/(2u−1))−1
⇒ (2u+3)(u−1)=(((1−u))/(2u−1))
⇒ u=1 or (2u+3)(2u−1)+1=0
or 4u^2 +4u−2=0
or 2u^2 +2u−1=0
⇒ u=((−2±(√(4+8)))/4) =((−1±(√3))/2)
for u_1 =1 , v_1 =(u_1 /(2u_1 −1))=1
so x_1 =((v_1 −u_1 )/2)=0 and
y_1 =((v_1 +u_1 )/2) =1
hence z_1 =i
for u_2 =(((√3)−1)/2) , v_2 =(((√3)−1)/(2((√3)−1−1)))
=−((((√3)−1)(2+(√3)))/2)
=−((((√3)+1))/2)
x_2 =((v_2 −u_2 )/2)=−((√3)/2)
y_2 =((v_2 +u_2 )/2) =−(1/2)
hence z_2 =−(1/2)((√3)+i)
for u_3 =−((((√3)+1))/2)
v_3 =(u_3 /(2u_3 −1)) =((((√3)+1))/(2((√3)+2)))
=((((√3)+1)(2−(√3)))/2)
=(((√3)−1)/2)
x_3 =((v_3 −u_3 )/2)=((√3)/2) and
y_3 =((v_3 +u_3 )/2)=−(1/2)
⇒ z_3 =(1/2)((√3)−i)
So to summarize,
z_1 =i , z_2 =−(1/2)((√3)+i), and
z_3 =(1/2)((√3)−i) .
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