The 12-m diameter spherical balloon is filled with helium that is at a temperature of 25°C and an absolute pressure of 130kPa. Determine the weight of the helium contained in the balloon

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.

d) physical means can be used to separate the components of air.

i think the answer is a, hope this : )