Description: The absolute value of a nonzero number is a positive real. (Contributed by Mario Carneiro, 29-May-2016)
Ref | Expression | ||
---|---|---|---|
Hypotheses | abscld.1 | |- ( ph -> A e. CC ) |
|
absne0d.2 | |- ( ph -> A =/= 0 ) |
||
Assertion | absrpcld | |- ( ph -> ( abs ` A ) e. RR+ ) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | abscld.1 | |- ( ph -> A e. CC ) |
|
2 | absne0d.2 | |- ( ph -> A =/= 0 ) |
|
3 | absrpcl | |- ( ( A e. CC /\ A =/= 0 ) -> ( abs ` A ) e. RR+ ) |
|
4 | 1 2 3 | syl2anc | |- ( ph -> ( abs ` A ) e. RR+ ) |