Find the curve's unit tangent vector. Also, find the length of the indicated portion of the curve. (t) = (3t sint+ 3 cost)i + (3t cost - 3 sint)j 1/2 sts2 The curve's unit tangent vector is k. The length of the indicated portion of the curve is units. (Simplify your answer.)\fFind T, N, and * for the space curve r(t) = (- 5e cost)i - (5e sint) j + 7k. T(t) = Dit k (Type exact answers, using radicals as needed.) N(t) = (Type exact answers, using radicals as needed.) K(t) = (Type an exact answer, using radicals as needed.)