Figure 2

Take \(\alpha _{1} = 5.5,\alpha _{2} = 5.25, \alpha _{3} =20.05, c = 50.75,\sigma = -2.09\) for 3D and contour plots of Eq. (23).

Take \(\alpha _{1} = 5.5,\alpha _{2} = 5.25, \alpha _{3} =20.05, c = 50.75,\sigma = -2.09\) for 3D and contour plots of Eq. (23).