[b]n=4[/b][br] [b]f₄(x, y) = k[sub]f[/sub]*(3 (1 - x²) ℯ[sup]-(x - 0.5)² - (y + 1)²[/sup] - 2 (x / 5 - x³ - y⁵) ℯ[sup]-x² - y²[/sup] sin(x - y))[/b][br][b][size=85][b] List of stationary points of the function f₄(x, y) found by CAS GeoGebra:[br][/b][color=#ff0000][u]Local maximum points[/u][/color]➟[/size][br][size=85] [color=#cc0000]{(0.2353663487636, -0.7526426338855), (-1.314409397085, 0.1107732423826), (-1.199524338384, 2.328080711288)}[/color];[/size][br][b][color=#0000ff][u][size=85]Local minimum points[/size][/u][/color]➟[br][/b][size=85][color=#1e84cc] {(1.577909225881, -1.118018998902), (-0.5170457911473, -1.81661036766), (-2.320827481355, 1.132720987397)(-0.004304874355589, 1.580056357246)}[/color][color=#0000ff];[/color][/size][br][color=#38761d][u][size=85]Saddle points[/size][/u][/color][b]➟[/b][size=85] [br][color=#6aa84f] {(-0.7208604308976, -0.1549572912881), (-1.758365538222, 1.382538064664)}.[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]