Abstract
In this work, we use the notion of (lambda, mu)-statistical convergence to prove the Korovkin-type approximation theorem for functions of two variables by using the test functions 1, x, y, x(2) + y(2). Furthermore, we define a new type of summability method via (lambda, mu)-statistical convergence and use it to prove Korovkin theorem. Moreover, we obtain order of (lambda, mu)-statistical convergence in our approximation.