Consider the curve $r(t)=($:$cos(5t),sin(5t),2t$:$).$

Find the principal unit normal vector,

$,N(t),to$ this curve $att=\frac{}{2}.$

$N(\frac{}{2})=$

Find a vector equation for the line normal

$.$

$bt=\frac{}{2}($:$x_0,y_0,z_0$:$)+t($:$a,b,c$:$).$