设向量满足||=||="1," ,则______.
复数z与(z+2)2-8i均为纯虚数,则z=________.
如果复数z= (b∈R)的实部和虚部互为相反数,则b=________.
复数z=(x2-1)+(x-1)i为纯虚数,则x=________.
方程x2+4=0的根为________.
已知a,b∈R,且a-1+2ai=-4+bi,则b=________.