find the curvature at the given point r(t) = (e-21, 21, 4), t = 0. Exercises find the curvature at the given point. S: 19. r(t) = (e-2t, 2t, 4), t = 0 20. r(t) = (2, sin at, In t), t = 1 21. r(t) = (t, sin 2t, 3t), t = 0 22. r(t) = (t. 1²2 +1 -1, 1), 1 = 0 In exercises 7-14, find the unit tangent vector to the curve at the indicated points. 7. r(t) = (31.F²), 1-0, r=-1.1-1 (A 8. r(t) = (21³, t),t = 1,t=2, t = 3 9. r(t) = (3 cos t, 2 sin t), t=0,t==₁t=A 10. r(t) = (4 sin 1, 2 cos r). 1 = -x, 1 = 0, 1 = 4 11. r(t)= (3r, cos 2r, sin 2r). t= 0, 1 =-₁1={A 12. r(t) = (t cost, t sint, 4t), t= -,t=0,t = 13. r(t) = (e²t cost, et sin t). t = 0.1=1,1=k {A 14. r(t) = (t - sint, 1 - cost), t = 0,t=₁t = k AN