A regular 5-polytope {,,,} exists only if {,,} and {,,} are regular 4-polytopes. The space it fits in is based on the expression: cos 2 ( π q ) sin 2 ( π p ) + cos 2 ( π r ) sin 2 ( π s ) {\displaystyle {\frac {\cos ^{2}\left({\frac {\pi }{q}}\right)}{\sin ^{2}\left({\frac {\pi }{p}}\right)}}+{\frac {\cos ^{2}\left({\frac ...