The graph of $r = \cos \theta$ is a circle.  Find the smallest value of $t$ so that when $r = \cos \theta$ is plotted for $0 \le \theta \le t,$ the resulting graph is the entire circle.
Question:
The graph of $r = \cos \theta$ is a circle.  Find the smallest value of $t$ so that when $r = \cos \theta$ is plotted for $0 \le \theta \le t,$ the resulting graph is the entire circle.
Answer:
Let's think step by step.

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The graph of $r = \cos \theta$ is a circle.  Find the smallest value of $t$ so that when $r = \cos \theta$ is plotted for $0 \le \theta \le t,$ the resulting graph is the entire circle.
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