證明：對于任意實數(shù)t，復數(shù)z=

|cost|

+

|sint|

i的模r=|z|適合r≤

4	2

．

證明在復數(shù)范圍內，方程|z|2+(1-i)

.

z

-(1+i)z=

5-5i

2+i

（i為虛數(shù)單位）無解．

證明:在復數(shù)范圍內,方程|z|²+(1-i)-(1+i)z=(i為虛數(shù)單位)無解.