Answer:
see below
Explanation:
We assume you want the graph of ...

A graphing calculator or spreadsheet is useful for this.
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You know cos(θ) = cos(-θ), so the graph is symmetrical about the x-axis. You can evaluate the function at a few points to find the general outline.
r at 0° = 8
r at 30° ≈ 7.05
r at 45° ≈ 6.19
r at 60° ≈ 5.33
r at 90° = 4
r at 120° = 3.2
r at 135° ≈ 2.96
r at 150° ≈ 2.79
r at 180° ≈ 2.67