·(3x^2tany-y^2sinx)dx+(x^2sec^2y+2ycosx-4)dy=0如何求通解?

·(3x^2tany-y^2sinx)dx+(x^2sec^2y+2ycosx-4)dy=0如何求通解?
·(3x^2tany-y^2sinx)dx+(x^2sec^2y+2ycosx-4)dy=0如何求通解?

·(3x^2tany-y^2sinx)dx+(x^2sec^2y+2ycosx-4)dy=0如何求通解?
(3x²tany - y²sinx)dx + (x²sec²y + 2ycosx - 4)dy = 0
tany dx³ + y²dcosx + x²dtany + cosx dy² - 4dy = 0
d(y²cosx - 4) + tany dx³ + x²dtany = 0
是不是题目错了?
应该是化成全微分