下面四個(gè)命題中正確的命題個(gè)數(shù)是

①0比－i大  ②兩個(gè)復(fù)數(shù)互為共軛復(fù)數(shù)，當(dāng)且僅當(dāng)其和為實(shí)數(shù)  ③x+yi=1+i的充要條件為x=y=1  ④如果讓實(shí)數(shù)a與ai對(duì)應(yīng)，那么實(shí)數(shù)集與純虛數(shù)集一一對(duì)應(yīng)

A.0                     B.1                 C.2                     D.3

已知z₁=2－i,z₂=1+3i，則復(fù)數(shù)的虛部為

A.1                 B.－1               C.i             D.－i

(1－i)²·i等于

A.2－2i             B. 2+2i             C.－2           D.2

復(fù)數(shù)z₁=3+i,z₂=1－i，則z=z₁·z₂在復(fù)平面內(nèi)的對(duì)應(yīng)點(diǎn)位于

A.第一象限                              B.第二象限

C.第三象限                              D.第四象限

(i－i^－1)³的虛部為

A.8i                    B.－8i              C.8                 D.－8

已知復(fù)數(shù)z與(z+2)²－8i均是純虛數(shù),則z等于

A.2i                   B.－2i               C.i                 D.－i

i是虛數(shù)單位,等于

A.1+i                                   B.－1－i

C.1+3i                                  D.－1－3i

已知復(fù)數(shù)z=3+4i且z(t－i)是實(shí)數(shù),則實(shí)數(shù)t等于

A.                B.                    C.－              D.－

過原點(diǎn)和－i對(duì)應(yīng)點(diǎn)的直線的傾斜角是

A.                B.－                  C.               D.

設(shè)ω=－+i,A={x|x=ω^k+ω^－k,k∈Z},則集合A中的元素有

A.1個(gè)                   B.2個(gè)               C.3個(gè)               D.4個(gè)