1.II.7A

Algebra and Geometry | Part IA, 2004

Simplify the fraction

ζ=1zˉ+1z+1zˉ,\zeta=\frac{1}{\bar{z}+\frac{1}{z+\frac{1}{\bar{z}}}},

where zˉ\bar{z} is the complex conjugate of zz. Determine the geometric form that satisfies

Re(ζ)=Re(z+14z2)\operatorname{Re}(\zeta)=\operatorname{Re}\left(\frac{z+\frac{1}{4}}{|z|^{2}}\right)

Find solutions to

Im(logz)=π3\operatorname{Im}(\log z)=\frac{\pi}{3}

and

z2=x2y2+2ix,z^{2}=x^{2}-y^{2}+2 i x,

where z=x+iyz=x+i y is a complex variable. Sketch these solutions in the complex plane and describe the region they enclose. Derive complex equations for the circumscribed and inscribed circles for the region. [The circumscribed circle is the circle that passes through the vertices of the region and the inscribed circle is the largest circle that fits within the region.]

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