问题
填空题
f（x）=
|
答案
因为f（x）=
，所以f′(x)=x2 cosx
=(x2)′•cosx-x2•(cosx)′ cos2x
．2x•cosx+x2•sinx cos2x
所以f′（π）=
=-2π．2πcosπ+π2sinπ cos2π
故答案为-2π．
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f（x）=
|
因为f（x）=
，所以f′(x)=x2 cosx
=(x2)′•cosx-x2•(cosx)′ cos2x
．2x•cosx+x2•sinx cos2x
所以f′（π）=
=-2π．2πcosπ+π2sinπ cos2π
故答案为-2π．