cos³二分之x求导数?
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发布时间:2022-05-02 19:51
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热心网友
时间:2022-06-26 14:00
记y=u^3,u=cosv, v=x/2, 则v'=1/2, u'=v'cosv=1/2·cos(x/2),
y'=3u'u^2=3/2·cos(x/2)(cosv)^2=3/2·cos(x/2)(cos(x/2))^2=3/2·(cos(x/2))^3.
热心网友
时间:2022-06-26 14:00
设u=cos(x/2),v=x/2
[cos(x/2)]^3} '= [ (u)^3] '=3u² v'
=3 { [cos(x/2)] ²}[cos(x/2)] '
=3 { [cos(x/2)] ^2} [-sin(x/2)] (x/2) '
=-3 { [cos(x/2)] } [2cos(x/2)sin(x/2)]/2 (1/2)
热心网友
时间:2022-06-26 14:01
解[cos(x/2)]'
=-sinx/2(x/2)'
=-1/2sin(x/2)追问审审题