## Thomas' Calculus 13th Edition

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Let us Consider, $c(t)=\lt c_1, c_2, c_3 \gt$ Here, $c_1, c_2, c_3$ refers to constants Since, $u=c$ and $\dfrac{d}{dt}(u)=\dfrac{d}{dt}c$ Thus, we have $u'=\lt \dfrac{d}{dt}(c_1), \dfrac{d}{dt}(c_2), \dfrac{d}{dt}(c_3) \gt$ so, $u'=\lt 0,0,0 \gt =0$