对xæ±å¯¼ï¼3x^2+3y^2*y'-3a(y+xy')=0,
æ以dy=(ay-x^2)/(y^2-ax).
å½y'=2x/(x^2+1)=0, x=0, å¨(-â,0)éåï¼å¨(0,+â)éå¢
å½y''=2(1-x^2)/(x^2+1)=0, x=1,-1ï¼ å¨(-1,1)为å¹å½æ°ï¼å¨(-â,-1),(1,+â)为å¸å½æ°
代å
¥x=0ï¼y''>0,æ以y(0)=2æ¯æå°å¼.
x=1ï¼-1为æç¹
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