DynCont#12: Eigen value and eigen vector 3Blue1Brown

• A vector will span a line passing through it. All points along the span, the line, can be reached by the vector using scalar multiplication.
  
•  A matrix multiplication rotates and scales a vector
• A matrix multiplication will only scale a Eigen vector , without changing its span direction.
• A rotation matrix has no eigen vector. All vectors are rotated.
• A shear matrix has one eigen vector.
• There are matrices with one eigen value and many eigen vectors, like scaling all vectors on a plane.
• See these 3 matrices and one normal eigen vector eigen value matrix in 2GBAB.