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  2. Direction cosine - Wikipedia

    en.wikipedia.org/wiki/Direction_cosine

    If vectors u and v have direction cosines (α u, β u, γ u) and (α v, β v, γ v) respectively, with an angle θ between them, their units vectors are ^ = + + (+ +) = + + ^ = + + (+ +) = + +. Taking the dot product of these two unit vectors yield, ^ ^ = + + = ⁡, where θ is the angle between the two unit vectors, and is also the angle between u and v.

  3. Dot product - Wikipedia

    en.wikipedia.org/wiki/Dot_product

    Illustration showing how to find the angle between vectors using the dot product Calculating bond angles of a symmetrical tetrahedral molecular geometry using a dot product. In Euclidean space, a Euclidean vector is a geometric object that possesses both a magnitude and a direction. A vector can be pictured as an arrow.

  4. Vector projection - Wikipedia

    en.wikipedia.org/wiki/Vector_projection

    Since the notions of vector length and angle between vectors can be generalized to any n-dimensional inner product space, this is also true for the notions of orthogonal projection of a vector, projection of a vector onto another, and rejection of a vector from another. In some cases, the inner product coincides with the dot product.

  5. Cosine similarity - Wikipedia

    en.wikipedia.org/wiki/Cosine_similarity

    The angle between two term frequency vectors cannot be greater than 90°. If the attribute vectors are normalized by subtracting the vector means (e.g., ¯), the measure is called the centered cosine similarity and is equivalent to the Pearson correlation coefficient. For an example of centering,

  6. Angle - Wikipedia

    en.wikipedia.org/wiki/Angle

    The angle between two planes (such as two adjacent faces of a polyhedron) is called a dihedral angle. [18] It may be defined as the acute angle between two lines normal to the planes. The angle between a plane and an intersecting straight line is complementary to the angle between the intersecting line and the normal to the plane.

  7. Spherical law of cosines - Wikipedia

    en.wikipedia.org/wiki/Spherical_law_of_cosines

    Let u, v, and w denote the unit vectors from the center of the sphere to those corners of the triangle. We have u · u = 1, v · w = cos c, u · v = cos a, and u · w = cos b.The vectors u × v and u × w have lengths sin a and sin b respectively and the angle between them is C, so ⁡ ⁡ ⁡ = () = () () = ⁡ ⁡ ⁡

  8. Inner product space - Wikipedia

    en.wikipedia.org/wiki/Inner_product_space

    Geometric interpretation of the angle between two vectors defined using an inner product Scalar product spaces, over any field, have "scalar products" that are symmetrical and linear in the first argument. Hermitian product spaces are restricted to the field of complex numbers and have "Hermitian products" that are conjugate-symmetrical and ...

  9. Euclidean vector - Wikipedia

    en.wikipedia.org/wiki/Euclidean_vector

    Subtraction of two vectors can be geometrically illustrated as follows: to subtract b from a, place the tails of a and b at the same point, and then draw an arrow from the head of b to the head of a. This new arrow represents the vector (-b) + a, with (-b) being the opposite of b, see drawing. And (-b) + a = a − b. The subtraction of two ...