/sci/ - Science & Math

Guys, I know OP's question was stupid, but does anyone know the proof of
<span class="math"> \forall a \leqslant 0 , a \in \mathbb{Z} / a^{2} = \abs{a}^{2}
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Like, the real mathematical proof where that happens (notice that you'll have to prove that (-1)^2 = 1 AND that a*(-1) = -a ).

picture unrelated

>>5138064
Second year here, and I'm just learning latex because I'm taking a computer science course.. If I wasn't, I could learn latex in a year. We do real maths before acknowledging computers even exists.