log10(e^-xcosπx)求导

问题描述:

log10(e^-xcosπx)求导

这道题的正确答案是什么.求大神解答


1个回答 分类:数学 2014-12-11

问题解答:

我来补答
=1/(ln10)[e^(-x)*cos(pi x)]*[e^(-x)cos(pi x)]'
=1/(ln10)[e^(-x)*cos(pi x)]*[-e^(-x)cos(pi x)-e^(-x)(-pi sin(pi x))]
=[-cos(pi x)+pi sin(pi x)]/[ln(10) cos(pi x)]
 
 
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