3. (5 points) (a): Find parametric equations for the tangent line to the curve with the given parametric equations at the specified point.
x=e−tcost,y=e−tsint,z=e−t;(1,0,1)(b): Find the unit tangent vector
T, the principal unit normal
N, and the curvature
κ for the space curve,
r(t)=<33=""4=""sin=""cos=""t="">