Question

Prove that a^2>0implies that a>0

Answer 1

No it's no true
a^2>0
\[=> a>0 or a<0\]

Answer 2

here is my proof
\[(-2)^2=4>0\] but
\[-2<0\] so we have a counter example
therefore it is not true that
\[a^2>0\implies a>0\]