$($f$)$ For one dimensional bound state motion of a particle of mass $m,$ prove that the expectation value of its kinetic energy is given by $($:$K$:$)=\frac{{}^2}{2m}{\displaystyle \underset{-}{\overset{}{}}}\frac{\text{d}\text{e}\text{l}}{\text{d}\text{e}\text{l}\text{x}}\frac{\text{d}\text{e}\text{l}**}{\text{d}\text{e}\text{l}\text{x}}dx.$