13. Consider the curve r(t) = (3t²1, t³ +7,5t + 4t²). (a) Does this curve intersect the point (11,−1,6)? If so, at what t-value? (b) Does this curve intersect the point (2,8, –1)? If so, at what t-value? (c) What vector is tangent to the curve at the point when t = 2? (d) What line is tangent to the curve at the point when t = 2?