1、(a+b)*(a-b)=|a|^2-|b|^2=1-1=0 即向量a+b与a-b互相垂直
2、│√3a+b│=│a-√3b│
3a^2 +2√3ab+b^2=a^2-2√3ab-3b^2
4√3ab = -2a^2 -4b^2= -6
ab= -√3/2 = |a|*|b|cosα=1×1×cosα,则cosα= -√3/2 ,则 α =150°