Apyshev О. , Nurkanova .Р. and Аmenova .Ф. 2020. APPLICATION OF INVARIANCE PROPERTIES IN PROBLEMS DEPENDING ON THE PARAMETER. Bulletin of Abai KazNPU. Series of Physical and Mathematical sciences. 70, 2 (Jun. 2020), 47–52. DOI:https://doi.org/10.51889/2020-2.1728-7901.06 .