Let $\mathbf { r } ( t ) = \cos ( t ) \mathbf { i } - \sin ( t ) \mathbf { j } + \pi t \mathbf { k }$ Then the unit normal vector $\mathbf { r } ( t ) = \cos ( t ) \mathbf { i } - \sin ( t ) \mathbf { j } + \pi t \mathbf { k }$ is

A) $- \mathbf { i }$
B)k
C)i
D)j
E) $- \mathbf { k }$

Question

Let

\mathbf { r } ( t ) = \cos ( t ) \mathbf { i } - \sin ( t ) \mathbf { j } + \pi t \mathbf { k }

Then the unit normal vector

\mathbf { r } ( t ) = \cos ( t ) \mathbf { i } - \sin ( t ) \mathbf { j } + \pi t \mathbf { k }

is

A) $- \mathbf { i }$
B)k
C)i
D)j
E) $- \mathbf { k }$

Quizplus · Accepted Answer

The Answer of Let $\mathbf { r } ( t ) = \cos ( t ) \mathbf { i } - \sin ( t ) \mathbf { j } + \pi t \mathbf { k }$ Then the unit normal vector $\mathbf { r } ( t ) = \cos ( t ) \mathbf { i } - \sin ( t ) \mathbf { j } + \pi t \mathbf { k }$ is

A) $- \mathbf { i }$
B)k
C)i
D)j
E) $- \mathbf { k }$

Let r(t)=cos⁡(t)i−sin⁡(t)j+πtk\mathbf { r } ( t ) = \cos ( t ) \mathbf { i } - \sin ( t ) \mathbf { j } + \pi t \mathbf { k }r(t)=cos(t)i−sin(t)j+πtk

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