21.指出下列各题中点z的轨迹或所在范围,并作图:-|||-(1) |z-5|=6 ;-|||-(2) |z+2i|geqslant 1 ;-|||-(3) Re(z+2)=-1 ;-|||-(4) (i)=3 ;-|||-(5) |z+i|=|z-i| ;-|||-(6) |z+3|+|z+1|=4 ;-|||-(7) ln (z)leqslant 2 ;-|||-(8) |dfrac (z-3)(z-2)|geqslant 1 ;-|||-(9) lt arccos xlt pi ;-|||-(10) (z-i)=dfrac (pi )(4) -

3.7 计算 (theta )_(1)=1=3=dfrac (1)((z-i)(z+2))dz .

1.3 解方程组 ) 2(z)_(1)-(z)_(2)=i (1+i)(z)_(1)+i(z)_(2)=4-3i .

1.下列函数有些什么奇点?如果是极点,指出它的级:(1)(1)/(z(z^2)+1)^(2); (2)(sin z)/(z^3); (3)(1)/(z^3)

设(z)=1-overline (z), _(1)=2+3i _(2)=5-i, 则 ([ f({z)_(1)-(z)_(2))-|||-__等于设等于

下列命题错误的是：((z)_(1)z)=(l)_(n)(z)_(1)+(I)_(n)(z)_(2)((z)_(1)z)=(l)_(n)(z)_(1)+(I)_(

5.设z_(1)及z_(2)是两复数.求证:(1)|z_(1)-z_(2)|^2=|z_(1)|^2+|z_(2)|^2-2mathrm(Re)(z_(1)ov

1.12 指出满足下列各式的点z的轨迹是什么曲线?-|||-(1) |z+i|=1 ;-|||-(2) |z-a|+|z+a|=b ,其中a,b为正实常数;-|

1.12 指出满足下列各式的点z的轨迹是什么曲线?-|||-(1) |z+i|=1;-|||-(2) |z-a|+|z+a|=b, 其中a,b为正实常数;-||

1.12 指出满足下列各式的点z的轨迹是什么曲线?-|||-(1) |z+i|=1 ;-|||-(2) |z-a|+|z+a|=b ,其中a,b为正实常数;-|

[单选题]若复数z1=1+i，z2=3-i，则z1·z2=（ ）A．4+2 i B. 2+ i C. 2+2 i D.3