PQSofQisthepointontheline PQthatliesintheplaneTondanexplicitformulaforfQwriteQabcdTheline PQis PQfabcd2P1RgThislinemeetswhend0sodThusfQad ID: 237335
PQ\.Sof(Q)isthepointontheline PQthatliesintheplane.Tondanexplicitformulaforf(Q) writeQ=[a;b;c;d].Theline PQis PQ=f[+a;+b;+c;+d]:[;]2P1(R)g:Thislinemeetswhen+d=0