*Problem:*

Given the family of parametric equations

**
x = (a + cos(3t)) cos(t)
**
and
y = (a + cos(3t)) sin(t)
with parameter **a**, draw the graphs for various values of **a**
between **-2** and **2**.

*Visualization:*

The following LiveMath notebook contains an animation which draws the desired
graphs as **a** ranges from **-2** to **2** in steps of **0.2**.
In addition, you can change the values of the constants in the equations and
see the effect on the graph. View an
animation to see how this can be done.