Upper and lower energy estimates for few-body nuclear and Coulomb systems

In the framework of the variational method with trial functions of the exponential and Gauss types, upper and lower estimates of energy for nuclear type systems and for the Coulomb systems of three, four and five particles have been found. The douЫe-ended estimates of energy not only allow one to find the exact energy range, but also provide an extra possibllity of extrapolation to the exact energy value. In this way, within the same accuracy, smaller volume of calculations can Ье performed using а lesser number of trial functions.