A generic drug is the same as a brand-name drug in dosage, safety, strength, quality, the way it works, the way it is taken and the way it should be used. FDA requires generic drugs have the same high quality, strength, purity and stability as brand-name drugs.
A matrix is a rectangular array of numbers arranged in rows and columns. The array of numbers below is an example of a matrix. The number of rows and columns that a matrix has is called its dimension or its order. By convention, rows are listed first; and columns, second.
A diagonal matrix in which all the diagonal elements are equal is called a scalar matrix. This kind of matrix is equal to the identity matrix multiplied by a scalar. Diagonal matrices have much simpler rules of addition and multiplication than general square matrices.