Find $r^{\text{'}}(t)$ and $r^{\text{'}\text{'}}(t)of$ the vector function $r(t)=7ti+6t^{3}j.$

$(Give$ your answer using component form $or$ standard basis vectors. Express numbers $in$ exact form. Use symbolic notation and

fractions where needed.$)$

$r^{\text{'}}(t)=$

$r^{\text{'}\text{'}}(t)=$