æ¹ç¨F(xï¼y)=e^y+xy-e=0è§å®äºy=f(x)ï¼ä¸è§£æ¹ç¨æ±dy/dx.
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d(e^y)/dx=[d(e^y)/dy](dy/dx)=(e^y)(dy/dx)ï¼èxyæ¢æ¯xçå½æ°ï¼åæ¯yçå½æ°ï¼yåæ¯xçå½æ°ï¼å æ¤
d(xy)/dx=(dx/dx)y+x(dy/dx)=y+x(dy/dx)ï¼
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çå¼ä¸¤è¾¹å¯¹xæ±å¯¼å¾ï¼(e^y)(dy/dx)+y+x(dy/dx)=0ï¼æ
dy/dx=-y/(x+e^y).
(2)ç¨éå½æ°æ±å¯¼å
¬å¼æ±å¯¼ï¼æ¹ç¨F(xï¼y)=0è§å®äºy=f(x)ï¼é£ä¹dy/dx=-(∂F/∂x)/(∂F∂y).
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ä¾å¦ï¼å·²ç¥xy²+3xlny+4x³=5x³y+6yï¼ä¸è§£æ¹ç¨æ±dy/dx
解ï¼ææ¹ç¨æ¹åæF(xï¼y)=xy²+3xlny+4x³-5x³y-6y=0
é£ä¹dy/dx=-(∂F/∂x)/(∂F/∂Y)=-(y²+3lny+12x²-15x²y)/[2xy+(3x/y)-5x³-6]
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