from University of Tokyo Mechanics A

  • Basis Vectors:
    • By combining basis vectors, any vector can be represented.
    • It is important that these are orthogonal.
      • It seems that they are called orthonormal basis vectors.
      • There are also non-orthogonal bases, but the commonly used ones are orthonormal bases (takker).
        • The importance of this will become clear as you perform calculations involving matrices and coordinate transformations.