What is third law of motion​

Newton's Third Law of Motion states: 'To every action there is an equal and opposite reaction'. ... The Third Law of Motion indicates that when one object exerts a force on another object, the second object instantaneously exerts a force back on the first object.

i think it because equal matrices have equal dimensions, only square matrices can be symmetric. for all indices and . every square diagonal matrix is symmetric, since all off-diagonal elements are zero. in linear algebra, a real symmetric matrix represents a self-adjoint operator over a real inner product space.

it doesn't. it was imagined up in the middle ages.