Can you show how to do this using Wolfram

To create the unit tangent vector T(t), try T[t_]:=r[t]/Sqrt[Dot[r[t],r[t]]] This creates the velocity vector rA(t) and divides it by its magnitude rA(t) to make T a unit-length vector. Then just type and execute T[t] on the next line. You may see 25cos2(t)+25sin2(t) expressions which should be replaced by just 25 . To make Mathematica simplify further, try T[t_]:=r[t]/Sqrt[Dot[r[t],r[t]]]//FullSimplify If you rerun T[t], it should look simpler. Now use the //N computation to compute T(4), to the nearest hundredth for each coordinate: T(4)=x,x,x