MP=(Sin^2)*MA+(Cos^2)*MB (MA,MB,MP均为向量),如何证明A,B,P三点共线?

MP=(Sin^2)*MA+(Cos^2)*MB (MA,MB,MP均为向量),如何证明A,B,P三点共线?
MP=(Sin^2)*MA+(Cos^2)*MB (MA,MB,MP均为向量),如何证明A,B,P三点共线?

MP=(Sin^2)*MA+(Cos^2)*MB (MA,MB,MP均为向量),如何证明A,B,P三点共线?
就是嘛,我说刚刚怎么那么奇怪
MP=MA+AP=MB+BP
AP=(Sin^2)*MA+(Cos^2)*MB-MA=Cos^2(MB-MA)=Cos^2AB
BP=(Sin^2)*MA+(Cos^2)*MB-MB=Sin^2(MA-MB)=-Sin^2(MB-MA)=-Sin^2AB
即-APSin^2=BPCos^2
BP=-tan^2AP
所以A,B,P三点共线