text: Kua whakapūtātia tētahi matapae mahere porotakaroa mā te tātai e hono ana i ngā taururuku taunaha o te pae rārangitanga o te φ me te roanga atu ki te Cartesian ka tauritea i runga i te mahere me te takenga o te paewae me te tuaka x i te taiapa.