#10, 21, 26

In Exercises 9-12., find the equation of the line tangent to the curve at the indicated t-value using the unit tangent vector. Note: these are the same problems as in Exercises S.-S.. 9. 7 (1) = (212 , +2 - t). t = 1 10. 7(t) - (t, cost). t - m/4\fIn Exercises 25-30., find ar and an given r (t). Sketch r (t) on the indicated interval, and comment on the relative sizes of aT and on at the indicated t values. 25- 7 (t) = (t, t?) on [-1, 1]; consider t = 0 and t = 1. o-T (t) = (t, 1/t) on (0, 4); consider t = 1 and t = 2