When $-24 + 7i$ is converted to the exponential form $re^{i \theta}$, what is $\cos \theta$?
<|im_start|>system
You are a helpful assistant.<|im_end|>
<|im_start|>user
When $-24 + 7i$ is converted to the exponential form $re^{i \theta}$, what is $\cos \theta$?
Please reason step by step, and put your final answer within \boxed{{}}.<|im_end|>
<|im_start|>assistant

user
-\frac{24}{25}
When $-24 + 7i$ is converted to the exponential form $re^{i \theta}$, what is $\cos \theta$?
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