[b]n=1[/b][br] [b]f₁(x, y) = k[sub]f[/sub]*(x[sup]4[/sup]+y[sup]4[/sup]-8*x[sup]2[/sup]-18*y[sup]2[/sup]-2 )[/b][br][b][size=85][b] List of stationary points of the function f[b]₁[/b](x, y) found by CAS GeoGebra:[br][/b][color=#ff0000][u]Local maximum points[/u][/color]➟[/size][br][size=85] [color=#a61c00]{(0, 0)}[/color];[/size][br][b][color=#0000ff][u][size=85]Local minimum points[/size][/u][/color]➟[br][/b][size=85][color=#1e84cc] {(2, 3), (-2, -3), (-2, 3), (2, -3)}[/color][color=#0000ff];[/color][/size][br][color=#38761d][u][size=85]Saddle points[/size][/u][/color][b]➟[/b][size=85] [br][color=#6aa84f] {(2, 0), (0, 3), (-2, 0), (0, -3)}.[br][br][/color][color=#333333]*Detailed instructions and explanations for this applet can be found in the previous [url=https://www.geogebra.org/m/vdfrrapq]applet[/url].[/color][/size][/b]