If $n$ is an integer and $Z=\cos \theta+i \sin \theta, \theta \neq(2 n+1) \frac{\pi}{2}$, then $\frac{1+Z^{2 n}}{1-Z^{2 n}}=$

The complex conjugate of $(4-3 i)(2+3 i)(1+4 i)$ is.

If the amplitude of $(z-2)$ is $\frac{\pi}{2}$, then the locus of $z$ is

If $\omega$ is the cube root of unity, $$ \frac{a+b \omega+c \omega^2}{c+a \omega+b \omega^2}+\frac{a+b \omega+c \omega^2}{b+c \omega+b \omega^2}= $$