【正文】
如: 有些方程則不能解出 y,如 等, 對于這樣的隱函數(shù)可不必解出 y,而是將 y作為 x的 函數(shù)隱藏在方程中利用隱函數(shù)求導法則求出其導數(shù) , 22222 xRyRyx ?????0s i n ??? yxy ?導數(shù)與微分 隱函數(shù)的求導法則: 將 y作為 x的函數(shù), y= y(x),于是 F(x, y(x))= 0 對方程兩邊的 x求導,遇 y時,將 y作為中間變量, 利用復合函數(shù)求導法則對 y求導再乘 得到一個含的方程,最后從新方程中解出 y?y?y?y?導數(shù)與微分 ? 例 6:求下列函數(shù)的導數(shù) yyyyyyyyxys i n111)s i n1(0s i n10s i n1)????????????????????解:(導數(shù)與微分 exeeyyxxeeyexeyyxeeyyxeyxyyyyyyyyyy?????????????????????????01|1)0(101)1(0)0(12)時解:求(導數(shù)與微分 25|1)2(21|1)2()4,2(),0,2(,4,0,44421,22222)2(223)420221222????????????????????????????????????????yxyxyxyxyyxyxyyyyyxyxyxyyyyxyxyxyxyx及解得代入原方程:將解:求(導數(shù)與微分 yxyxyxyxyxyxyxexyeyyeexyyeyxyexyexy?????????????????????????)()1()()(4)解:(導數(shù)與微分 )]()()()(ln)([)]([)()()()(ln)(1)(ln)(ln:)]([.4)()(xfxfxgxfxgxfyxfxfxgxfxgyyxfxgyxfyxgxg?????????????取對數(shù)化成隱函數(shù)數(shù)皆為變量)稱為冪指函數(shù)(底和指冪指函數(shù)求導法則導數(shù)與微分 )s i nln( c oss i nlnc os1lns i nlnln)2().ln1(1ln1,lnln1)7s i ns i ns i nxxxxxyxxxxyyxxxyxyxxyxxxyyxxyxyxxxxx???????????????????(:求下列函數(shù)的導數(shù)例導數(shù)與微分 )ln()ln(ln)( l nlnlnlnln,lnln3)xxyxyyxyyxyyyxxyyyxyxyxyyxxyyxyxxyxy??????????????????(導數(shù)與微分 ? 注:對一些較復雜的乘積,商或根式函數(shù)求導時,可利用先取對數(shù)后求導的方法計算 62333623232333333333121112)1313(311)]1l n ()1[ l n (3111ln31)11l n (ln11)4(31xxxxyxxxxxxyyxxxxxxyxxy???????????????????????????解:導數(shù)與微分 2111111))1( l n ()()()()()1l n (1)8)()()()()(:2tttar c t gttxtyxyar c t gtytxtxtyxyttyytxxtt??????????????????????????????(的函數(shù)的導數(shù):求下列參數(shù)方程給出例