use ContourPlot-使用ContourPlot

use ContourPlot to draw implicit function graphics

使用ContourPlot 画隐函数图像

for example $x^{3}+y^{3}-3xy=0$

use ContourPlot to draw integral curve

使用ContourPlot 画积分曲线

for example $y{}‘=xy-e^{-x^{2}}y^{3}$

solve it get  $y=\frac{e^{x^{2}/2}}{\sqrt{2x+c}},y=-\frac{e^{x^{2}/2}}{\sqrt{2x+c}}$

then get $c=\frac{e^{x^{2}}}{y^{2}}-2x$

then ContourPlot[$c=\frac{e^{x^{2}}}{y^{2}}-2x$,$\left \{ x,-3,3 \right \}$,$\left \{ y,-3,3 \right \}$]