（dy/dx）*2y=(x*y^2+sinx）设p=y²,dp/dx=2y*dy/dx原式=dp/dx-px=sinx两边同乘e^(-x²/2),左右同时积分，p*e^(-(x^2)/2)=∫sinx *e^(-(x^2)/2),p=e^(x²/2)*∫sinx *e^-(x²/2),y=√(e^(x²/2)*∫sinx *e^-(x²/2))
