For the best answers, search on this site https://shorturl.im/8g1Rz. Before addressing the problem, consider a regular pentagon with unit sides. Draw a diagonal d and observe that d = 2*cos(36) from one side and d = 2*cos(72) + 1 from the other so that Â½ = cos(36) - cos(72) = cos(36) - (2cosÂ²(36)-1).
Ionic compound. In chemistry, an ionic compound is a chemical compound in which ions are held together in a lattice structure by ionic bonds. Usually, the positively charged portion consists of metal cations and the negatively charged portion is an anion or polyatomic ion.hus, in an ionic bond, one 'bonder' must have a positive charge and the other a negative one. By sticking to each other, they resolve, or partially resolve, their separate charge imbalances. Positive to positive and negative to negative ionic bonds do not occur. Chemical compounds are never strictly ionic.
A covalent compound is a compound in which the atoms that are bonded share electrons rather than transfer electrons from one to the other. While ionic compounds are usually formed when metals bond to nonmetals, covalent compounds are formed when two nonmetals bond to each other. covalent compound is a compound in which the atoms that are bonded share electrons rather than transfer electrons from one to the other. While ionic compounds are usually formed when metals bond to nonmetals, covalent compounds are formed when two nonmetals bond to each other.