Algebra-2

Question Analysis
This problem requires finding all values of in a given interval where the cosine function equals a specific value, testing the understanding of periodicity and symmetry.

Key Concept Explanation
The cosine function is periodic with a period of . In one period, at and . To find all solutions in the interval , we need to consider the periodicity and extend these solutions.

Step-by-step Solution
1. Identify the values of in one period where : and .
2. Extend these solutions to the interval by adding the period

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