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Chapter 10: Parametric Equations and Polar Coordinates

Learning module LM 10.1: Parametrized Curves:

      3 kinds of functions, 3 kinds of curves
      The cycloid
      Visualizing parametrized curves
      Tracing curves and ellipses
      Lissajous figures

Learning module LM 10.2: Calculus with Parametrized Curves:

Learning module LM 10.3: Polar Coordinates:

Learning module LM 10.4: Areas and Lengths of Polar Curves:

Learning module LM 10.5: Conic Sections:

Learning module LM 10.6: Conic Sections in Polar Coordinates:

Chapter 12: Vectors and the Geometry of Space


Chapter 13: Vector Functions


Chapter 14: Partial Derivatives


Chapter 15: Multiple Integrals



Tracing curves and ellipses

Tracing Curves and Ellipses

We already saw that $x=\cos(t)$, $y=\sin(t)$ gives a circle traced counter-clockwise. In this demonstration, we'll look at something slightly more complicated:$$x(t) = a\cos(t) + h, \qquad y(t)=b\sin(t)+k,$$where $a$, $b$, $h$ and $k$ are numbers that you specify.


Investigate the interactive figure to the right.
(i) Try changing $a$, $b$, $h$ and $k$, one at a time, to understand what each of them does.
(ii) How would you make a circle of radius 2, centered at the origin?
(iii) How would you make an ellipse centered at the origin that is twice as wide as it is high? Or half as wide as it is high?
(iv) How would you make a circle of radius 3, centered at the point (-1,4)?