1.
AB//(P)\Rightarrow d(A,(P))=d(B,(P))
d(A,(P))\le AC
\Rightarrow P= \alpha d(A,(P))+\beta d(B,(P))=\alpha d(A,(P))+\beta d(A,(P))=(\alpha+\beta)d(A,(P))\le (\alpha+\beta)AC
2.
IB=\dfrac{\alpha}{\beta}ID\Rightarrow \dfrac{d(B,(P))}{d(D,(P))}=\dfrac{\alpha}{\beta}
P=\alpha d(A,(P))+\beta...