#28: describe/explain three different types of waves regularly used by humans.

If I remember correctly, it was radio waves, microwaves, and visible light.

We use radio waves, like when your sitting in the car, and you turn on the radio for some music, or broadcast you wanna listen you.

We use microwaves, to cook our food faster.

We use visible light, so we can see things around us. Any other wave would be to dangerous for us.

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.