(8) Evaluate the Integral: (con (x1) 1+1+1) • dt. archant 7. (9) Let r(t) = ()+j+k, t>0. (a) Find r'(f). (b) Find a unit tangent vector to the curve r(f) at t=1. (c) Find parametric equations for the tangent line to the curve r(t) at the point (1.1. 1/4 8. (9) Find r(t). if (t) = (tint, te³-, t) and r(1) = (1.0.1).