In the following graph of y = a + bcoskq, a = 0, b = 2 and k = 3. Since k is odd, the graph has 3 petals. Notice that 2 is the maximum distance that the graph lies from the origin.

In the following graph of y = a + bcoskq, a = 0, b = 2 and k = 4. Since k is even, the graph has 2(4) or 8 petals. Notice once again that 2 is the maximum distance of the graph from the origin.

Finally, in the following graph of y = a + bcoskq, a = 0, b = 2 and k = 0. As expected, the equation graphs as a circle centered at the origin with a radius of 2.