Problem Set 62: Parametric Equations

1. What is a system of parametric equations?

2. Some examples of a third parameter are time, length, speed, and scale. Explain when time is used as a parameter.

3. Explain how to eliminate a parameter given a set of parametric equations.

4. What is a benefit of writing a system of parametric equations as a Cartesian equation?

5. What is a benefit of using parametric equations?

6. Why are there many sets of parametric equations to represent on Cartesian function?

For the following exercises, eliminate the parameter tt to rewrite the parametric equation as a Cartesian equation.

7. {x(t)=5ty(t)=82t{x(t)=5ty(t)=82t

8. {x(t)=63ty(t)=10t{x(t)=63ty(t)=10t

9. {x(t)=2t+1y(t)=3t{x(t)=2t+1y(t)=3t

10. {x(t)=3t1y(t)=2t2{x(t)=3t1y(t)=2t2

11. {x(t)=2ety(t)=15t{x(t)=2ety(t)=15t

12. {x(t)=e2ty(t)=2et{x(t)=e2ty(t)=2et

13. {x(t)=4log(t)y(t)=3+2t{x(t)=4log(t)y(t)=3+2t

14. {x(t)=log(2t)y(t)=t1{x(t)=log(2t)y(t)=t1

15. {x(t)=t3ty(t)=2t{x(t)=t3ty(t)=2t

16. {x(t)=tt4y(t)=t+2{x(t)=tt4y(t)=t+2

17. {x(t)=e2ty(t)=e6t{x(t)=e2ty(t)=e6t

18. {x(t)=t5y(t)=t10{x(t)=t5y(t)=t10

19. {x(t)=4costy(t)=5sint{x(t)=4costy(t)=5sint

20. {x(t)=3sinty(t)=6cost{x(t)=3sinty(t)=6cost

21. {x(t)=2cos2ty(t)=sint{x(t)=2cos2ty(t)=sint

22. {x(t)=cost+4y(t)=2sin2t{x(t)=cost+4y(t)=2sin2t

23. {x(t)=t1y(t)=t2{x(t)=t1y(t)=t2

24. {x(t)=ty(t)=t3+1{x(t)=ty(t)=t3+1

25. {x(t)=2t1y(t)=t32{x(t)=2t1y(t)=t32

For the following exercises, rewrite the parametric equation as a Cartesian equation by building an x-yx-y table.

26. {x(t)=2t1y(t)=t+4{x(t)=2t1y(t)=t+4

27. {x(t)=4ty(t)=3t+2{x(t)=4ty(t)=3t+2

28. {x(t)=2t1y(t)=5t{x(t)=2t1y(t)=5t

29. {x(t)=4t1y(t)=4t+2{x(t)=4t1y(t)=4t+2

For the following exercises, parameterize (write parametric equations for) each Cartesian equation by setting x(t)=tx(t)=t or by setting y(t)=ty(t)=t.

30. y(x)=3x2+3y(x)=3x2+3

31. y(x)=2sinx+1y(x)=2sinx+1

32. x(y)=3log(y)+yx(y)=3log(y)+y

33. x(y)=y+2yx(y)=y+2y

For the following exercises, parameterize (write parametric equations for) each Cartesian equation by using x(t)=acostx(t)=acost and y(t)=bsinty(t)=bsint. Identify the curve.

34. x24+y29=1x24+y29=1

35. x216+y236=1x216+y236=1

36. x2+y2=16x2+y2=16

37. x2+y2=10x2+y2=10

38. Parameterize the line from (3,0)(3,0) to (2,5)(2,5) so that the line is at (3,0)(3,0) at t=0t=0, and at (2,5)(2,5) at t=1t=1.

39. Parameterize the line from (1,0)(1,0) to (3,2)(3,2) so that the line is at (1,0)(1,0) at t=0t=0, and at (3,2)(3,2) at t=1t=1.

40. Parameterize the line from (1,5)(1,5) to (2,3)(2,3) so that the line is at (1,5)(1,5) at t=0t=0, and at (2,3)(2,3) at t=1t=1.

41. Parameterize the line from (4,1)(4,1) to (6,2)(6,2) so that the line is at (4,1)(4,1) at t=0t=0, and at (6,2)(6,2) at t=1t=1.

For the following exercises, use the table feature in the graphing calculator to determine whether the graphs intersect.

42. {x1(t)=3ty1(t)=2t1 and {x2(t)=t+3y2(t)=4t4{x1(t)=3ty1(t)=2t1 and {x2(t)=t+3y2(t)=4t4

43. {x1(t)=t2y1(t)=2t1 and {x2(t)=t+6y2(t)=t+1{x1(t)=t2y1(t)=2t1 and {x2(t)=t+6y2(t)=t+1

For the following exercises, use a graphing calculator to complete the table of values for each set of parametric equations.

44. {x1(t)=3t23t+7y1(t)=2t+3{x1(t)=3t23t+7y1(t)=2t+3

tt xx yy
–1
0
1

45. {x1(t)=t24y1(t)=2t21{x1(t)=t24y1(t)=2t21

tt xx yy
1
2
3

46. {x1(t)=t4y1(t)=t3+4{x1(t)=t4y1(t)=t3+4

tt xx yy
-1
0
1
2

47. Find two different sets of parametric equations for y=(x+1)2y=(x+1)2.

48. Find two different sets of parametric equations for y=3x2y=3x2.

49. Find two different sets of parametric equations for y=x24x+4y=x24x+4.