已知f(t)=t[u(t)-u(t-2)],怎么求df(t)/dt,请说的详细点

如题所述

第1个回答  2012-05-31
f(t)=t[u(t)-u(t-2)]
df(t)/dt = t (d[u(t)-u(t-2)]/dt ) + [u(t)-u(t-2)] dt/dt
= t[ u'(t) -u'(t-2) ] + [u(t)-u(t-2)]本回答被提问者采纳
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