Error with exp function and imaginary numbers

[John Keith]

For comparison, I get the following results with HP 50g:

EXP(-1E49) 0.
COS(-1E49) .814097070848


With LongFloat, 50 digits precision:

EXP(-1E49) 0.
COS(-1E49) -.9190287918554938...


Interesting that the 50g gives an erroneous answer for COS but a different one than the Prime.