Given vector PP1 = - (2 / 5) * vector p1p2, if vector p1p = λ PP2, then λ=

Given vector PP1 = - (2 / 5) * vector p1p2, if vector p1p = λ PP2, then λ=

P1P2=P1P+PP2
P1P=λPP2,∴PP2=1/λ P1P
∴P1P2=P1P+PP2=P1P+1/λ P1P
∴PP1==-P1P=-λ/(1+λ) P1P2
∴-λ/(1+λ)=-2/5
∴λ=2/3