mp*mn+nm*np=2pm*pnmp=(x+1,y) mn=(2,0) nm=-(2,0) np=(x-1,y)mp*mn+nm*np=mn(mp-np)=(2,0)(2,0)=42(x+1,y)(x-1,y)=2(x^2-1)+2y^2x^2+y^2=3cosa=pm*pn/|pm||pn|=(x0^2+y0^2-1)/2向量nm x向量np0 题设不问题....