1. The problem statement, all variables and given/known data In the variational method the ground state energy of a quantum system has been calculated as (ћω_o)f(λ), where f(λ) is a function of an arbitrary parameter λ. If f(λ)= λ² + λ, then what is the best estimate of the ground state energy. 3. The attempt at a solution Is this simply (ћω_o)f(λ² + λ). As the parameters of the ground state wave function have been found which give the lowest expectation value for the ground state energy.