DefinitionInner products and norms are key ideas in linear algebra and functional analysis. The most common basic operation connecting two vectors is the inner product, a more general form of the dot product, which provides a metric to compare angles and sizes in vector spaces, and has linearity, symmetry, and positive-definiteness properties. The derivative measure the length of vector, what it will give the geometrical norm, originated from the inner product. Inner products and norms allow us to examine the geometric and algebraic behaviors of spaces, such as orthogonality and distance. Example: For u,v∈Rn, ⟨u,v⟩=∑iuivi and∥u∥=⟨u,u⟩