“…Namely, in function approximation, under certain conditions, single-hidden-layer neural networks which called shallow neural networks can approximate well continuous functions on bounded domains. Networks with many hidden-layers called deep neural networks which revolutionized the field of approximation theory e.g., [1,3,4,5,6,12,11,16,19,20,21] and when solving partial differential equations using deep learning techniques [2,7,8,13,18,22]. In the literature, there exist several results about approximation properties of deep neural networks, where authors use different activation functions in order to unraveling the extreme efficiency of deep neural networks.…”