Let $\vec { r } ( t ) = \sin ( t ) \vec { i } + \cos ( t ) \vec { j } + t \vec { k }$

Essay

Let $\vec { r } ( t ) = \sin ( t ) \vec { i } + \cos ( t ) \vec { j } + t \vec { k }$ and let C be the helix parameterized by $\vec { r } ( t )$ Find an expression for the outward pointing normal vector whose $\vec { k }$ component is 0 at an arbitrary point ( sin(t), cos(t), t)of C.