4 (25 points) a) Use the variational method to determine the ground state energy of the hydrogen atom starting with the trial function (r)=e" , where a is the variational parameter andr has its usual meaning in spherical coordinates. The following integrals will be useful in your calculation, e? Jo Hor dr =; and Jo'or dr: 1 = 4a? 8m a 16TE a 4b) Rewrite the value of a you determined in answering part "a" as a function of the 4Te h? (- me? Bohr radius, ao. (a :