【正文】
)(()(,),(:)()(7)22222xxvvvxafaxaufaxaxaufyxvauufyafuf???????????????????)令的導(dǎo)數(shù)存在,求已知(導(dǎo)數(shù)與微分 ? 例 5:證明:偶函數(shù)的導(dǎo)數(shù)是奇函數(shù)。如: 有些方程則不能解出 y,如 等, 對(duì)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(dǎo)法則求出其導(dǎo)數(shù) , 22222 xRyRyx ?????0s i n ??? yxy ?導(dǎo)數(shù)與微分 隱函數(shù)的求導(dǎo)法則: 將 y作為 x的函數(shù), y= y(x),于是 F(x, y(x))= 0 對(duì)方程兩邊的 x求導(dǎo),遇 y時(shí),將 y作為中間變量, 利用復(fù)合函數(shù)求導(dǎo)法則對(duì) y求導(dǎo)再乘 得到一個(gè)含的方程,最后從新方程中解出 y?y?y?y?導(dǎo)數(shù)與微分 ? 例 6:求下列函數(shù)的導(dǎo)數(shù) yyyyyyyyxys i n111)s i n1(0s i n10s i n1)????????????????????解:(導(dǎo)數(shù)與微分 exeeyyxxeeyexeyyxeeyyxeyxyyyyyyyyyy?????????????????????????01|1)0(101)1(0)0(12)時(shí)解:求(導(dǎo)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(dǎo)數(shù)與微分 yxyxyxyxyxyxyxexyeyyeexyyeyxyexyexy?????????????????????????)()1()()(4)解:(導(dǎo)數(shù)與微分 )]()()()(ln)([)]([)()()()(ln)(1)(ln)(ln:)]([.4)()(xfxfxgxfxgxfyxfxfxgxfxgyyxfxgyxfyxgxg?????????????取對(duì)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(dǎo)法則導(dǎo)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(dǎo)數(shù)例導(dǎo)數(shù)與微分 )ln()ln(ln)( l nlnlnlnln,lnln3)xxyxyyxyyxyyyxxyyyxyxyxyyxxyyxyxxyxy??????????????????(導(dǎo)數(shù)與微分 ? 注:對(duì)一些較復(fù)雜的乘積,商或根式函數(shù)求導(dǎo)時(shí),可利用先取對(duì)數(shù)后求導(dǎo)的方法計(jì)算 62333623232333333333121112)1313(311)]1l n ()1[ l n (3111ln31)11l n (ln11)4(31xxxxyxxxxxxyyxxxxxxyxxy???????????????????????????解:導(dǎo)數(shù)與微分 2111111))1( l n ()()()()()1l n (1)8)()()()()(:2tttar c t gt