Note 1 to entry: A straight line passing through a point O is the set of points P with position vector rP=αV, where α is a scalar and V a non-zero vector of the vector space associated with the point space.
Note 1 to entry: A straight line passing through a point O is the set of points P with position vector r P =αV MathType@MTEF@5@5@+= feaagKart1ev2aqatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbbjxAHX garuavP1wzZbItLDhis9wBH5garmWu51MyVXgarqqtubsr4rNCHbGe aGqk0di9Wr=fpeei0di9v8qiW7rqqrVepeea0xe9LqFf0xc9q8qqaq Fn0lXdHiVcFbIOFHK8Feea0dXdar=Jb9hs0dXdHuk9fr=xfr=xfrpe WZqaaeaaciWacmGadaGadeaabaGaaqaaaOqaaiaahkhadaWgaaWcba qcLbmacaqGqbaaleqaaOGaeyypa0JaeqySdeMaaCOvaaaa@3F8E@ , where α is a scalar and V a non-zero vector of the vector space associated with the point space.