若＝a＋bi(a，b為實(shí)數(shù)，i為虛數(shù)單位)，則a＋b＝________.

已知集合M＝{1,2，zi}，i為虛數(shù)單位，N＝{3,4}，M∩N＝{4}，則復(fù)數(shù)z＝(　　)

A．－2i                                                         B．2i

C．－4i                                                         D．4i

復(fù)數(shù)z＝i(－2－i)(i為虛數(shù)單位)在復(fù)平面內(nèi)所對(duì)應(yīng)的點(diǎn)在(　　)

A．第一象限                                                 B．第二象限

C．第三象限                                                 D．第四象限

設(shè)a，b∈R，i是虛數(shù)單位，則“ab＝0”是“復(fù)數(shù)a＋為純虛數(shù)”的(　　)

A．充分不必要條件                                      B．必要不充分條件

C．充分必要條件                                          D．既不充分也不必要條件

在復(fù)平面內(nèi)，復(fù)數(shù)(2－i)²對(duì)應(yīng)的點(diǎn)位于(　　)

A．第一象限                                                 B．第二象限

C．第三象限                                                 D．第四象限

在復(fù)平面內(nèi)，復(fù)數(shù)i(2－i)對(duì)應(yīng)的點(diǎn)位于(　　)

A．第一象限                                                 B．第二象限

C．第三象限                                                 D．第四象限

在復(fù)平面內(nèi)，向量對(duì)應(yīng)的復(fù)數(shù)是2＋i，向量對(duì)應(yīng)的復(fù)數(shù)是－1－3i，則向量對(duì)應(yīng)的復(fù)數(shù)為(　　)

A．1－2i                                                       B．－1＋2i

C．3＋4i                                                       D．－3－4i

設(shè)i是虛數(shù)單位，是復(fù)數(shù)z的共軛復(fù)數(shù)，若z·i＋2＝2z，則z＝(　　)

A．1＋i                                                         B．1－i

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

設(shè)i是虛數(shù)單位，若復(fù)數(shù)a－(a∈R)是純虛數(shù)，則a的值為(　　)

A．－3                                                          B．－1

C．1                                                             D．3

若z＝，則復(fù)數(shù)＝(　　)

A．－2－i                                                     B．－2＋i

C．2－i                                                         D．2＋i