Answer: symmetric about the y-axis.
Explanation:
This time, I am going to use cartesian coordinates, with x = θ and y = r.
You can use the fact that the cosine function is an even function.
Since cosine function is even, the resulting function r = 5 + 4 cos θ is also even.
The even functions are those for which f(x) = f(-x), and that is that the function is symmetric about the y-axis. That yilelds the answer.
