HP Prime two questions about function app

[dg1969]

I place an order for these prime... The parcel is on the road... So I play with the emulator...

1) I try to find a way to plot a family function of one parameter:
F1(X)=(1-N)*EXP(-X) with N in {-1, -2, 2, 5}
for example...

2) If I define a function in the CAS : p(x):=sin(x)/x then
I can plot it in the function app with : F1(X)=p(X) but I can't use the "extremum" or "slope" functions... It's a bit frustrating !

Any idea ?

Thank's for your help.

Edited: 28 Sept 2013, 1:16 p.m.