a b s t r a c tIn this work, we consider the following isotropic mixed-type equations:By proving some Pohozaev-type identities for (0.1) and dividing B r (0) naturally into six regions Ω i (i = 1, 2, 3, 4, 5, 6), we can show that the equationwith Dirichlet boundary conditions on each natural domain Ω i has no nontrivial regular solution in B r (0).