A Child Is Sliding Down a Helical Slide $\vec { r } = \cos t \vec { i } + \sin t \vec { j } + ( 12 - t ) \vec { k }$

Short Answer

A child is sliding down a helical slide.Her position at time t after the start is given in feet by $\vec { r } = \cos t \vec { i } + \sin t \vec { j } + ( 12 - t ) \vec { k }$ .The ground is the xy-plane.
At time t = 2 $\pi$ , the child leaves the slide on the tangent to the slide at that point.What is the equation of the tangent line?