Let c$\_(1)($t$)=$e$^(5$t$)$i$+7$sin$($t$)$j$+$t$^(4)$k and c$\_(2)($t$)=$e$^(-5$t$)$i$+3$cos$($t$)$j$-4$t$^(4)$k$.$

$($Enter your solution as a single vector using the vector form $(,*).$ Use symbolic notation and fractions where needed.$)$

$($d$)/($dt$)[$c$\_(1)($t$)+$c$\_(2)($t$)]=$