If $\psi_{nx}(x)$ and $\psi_{ny}(y)$ are the eigensolutions and $E_{nx}$ and $E_{ny}$ are the eigenvalues of harmonic oscillator problem in x and y direction with potential $\frac{1}{2}k_x x^2$ and $\frac{1}{2}k_y y^2$ respectively, the wave function and eigenvalues of the above two-dimensional harmonic oscillator problem are