Description: Closure law for exponentiation of positive reals. (Contributed by Mario Carneiro, 28-May-2016)
Ref | Expression | ||
---|---|---|---|
Hypotheses | rpexpcld.1 | |- ( ph -> A e. RR+ ) |
|
rpexpcld.2 | |- ( ph -> N e. ZZ ) |
||
Assertion | rpexpcld | |- ( ph -> ( A ^ N ) e. RR+ ) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | rpexpcld.1 | |- ( ph -> A e. RR+ ) |
|
2 | rpexpcld.2 | |- ( ph -> N e. ZZ ) |
|
3 | rpexpcl | |- ( ( A e. RR+ /\ N e. ZZ ) -> ( A ^ N ) e. RR+ ) |
|
4 | 1 2 3 | syl2anc | |- ( ph -> ( A ^ N ) e. RR+ ) |