Description: A negative number is the negative of its own absolute value. (Contributed by NM, 2-Aug-1999)
Ref | Expression | ||
---|---|---|---|
Hypothesis | sqrtthi.1 | |- A e. RR |
|
Assertion | absnidi | |- ( A <_ 0 -> ( abs ` A ) = -u A ) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | sqrtthi.1 | |- A e. RR |
|
2 | absnid | |- ( ( A e. RR /\ A <_ 0 ) -> ( abs ` A ) = -u A ) |
|
3 | 1 2 | mpan | |- ( A <_ 0 -> ( abs ` A ) = -u A ) |