￡＝根号2·cos(@＋pi/4)两边平方￡=√[2cos^2(@＋π/4)]=√[cos(2@＋π/2)+1]=√(1-sin2@)=Isin@-cos@I两边同乘以￡ ￡^2=I￡sin@-￡cos@I所以x^2+y^2=Ix-yI故x^2+y^2-x+y=0 或x^2+y^2+x-y=0...