optimal coefficients method Warning message Node revision 628 not found in node Upper and low bounds of azimuthal numbers related to elementary wave functions of an elliptic cylinder . Perharps it was deleted. Node revision 508 not found in node Mechanical properties study for graphene sheets of various size . Perharps it was deleted. Some Questions of Number-theoretical Method in Approximation Analysis Authors: Dobrovolskaya L. P., Dobrovolsky M. N., Dobrovolskii N. M., Rebrova I. Y. This article gives an overview of several actual problems of optimal coefficients method. This overview was done on September 12, 2013 on XI internation conference «Algebra and number theory: modern problems and applications» in Saratov city. Read more about Some Questions of Number-theoretical Method in Approximation Analysis