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 ) |