问答题
解方程：=-scost+sin2t
解方程：（ylnx-2）ydx=xdyx2+
解答题：x=y+
解方程：（y+x）dy+（y-x）dx=0
问答题解方程：（y+x）dy+（y-x）dx=0
=-scost+
sin2t
x2+
=y+