Description: The terms of the series expansion of the exponential function at a real number are real. (Contributed by Paul Chapman, 15-Jan-2008)
Ref | Expression | ||
---|---|---|---|
Assertion | reeftcl | |- ( ( A e. RR /\ K e. NN0 ) -> ( ( A ^ K ) / ( ! ` K ) ) e. RR ) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | reexpcl | |- ( ( A e. RR /\ K e. NN0 ) -> ( A ^ K ) e. RR ) |
|
2 | faccl | |- ( K e. NN0 -> ( ! ` K ) e. NN ) |
|
3 | 2 | adantl | |- ( ( A e. RR /\ K e. NN0 ) -> ( ! ` K ) e. NN ) |
4 | 1 3 | nndivred | |- ( ( A e. RR /\ K e. NN0 ) -> ( ( A ^ K ) / ( ! ` K ) ) e. RR ) |