Chapter 2: Problem 4
If \(a \in \mathbb{R}\) satisfies \(a \cdot a=a\), prove that either \(a=0\) or \(a=1\).
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Chapter 2: Problem 4
If \(a \in \mathbb{R}\) satisfies \(a \cdot a=a\), prove that either \(a=0\) or \(a=1\).
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