negative exponential

Hi all
I need to know how to sample from a negative exponential distribution: i.e. an equation y=ae^-x.

I also need to be able to get a cumulative distribution from the equation...

And finally, does anyone know how to record a result from a macro and put it into a separate cell each time the macro is run? Is just a simple VBA trick, but can't remember for the life of me.

Any help on any of these would be much appreciated.

aj

Hi ajmac,

The attached EXCEL file responds to all your questions I guess. I hope you find it sufficiently instructive.

Don´t forget to activate the macro. ;)

Thanks Rassis,
after a day of thinking I've got my head more or less around it.
thanks for the quick reply, very impressive...

ajmac