Question

How do I differentiatie e to the power minus x?
So let's say: g(x) = e^-x. In steps please, I'm somewhat confused...

Answer 1

u=u(x)

\[(e^u)'=u'e^u \]

Answer 2

So we have u=-x
=> u'=-1
just plug in

Answer 3

let -x =y, hence dy/dx = -1, hence (d/dx)e^-x = (d/dy)e^y.(dy/dx) = e^y.(-1) = -e^y = -e^-x

Answer 4

Merci!

Answer 5

au revoir ( i don't know how to say your welcome in french :()

Answer 6

Haha, me neither :)

Answer 7

lol

Answer 8

I got it, Bienvenue!!!

Answer 9

Can I always "plug" in x = -1?

Answer 10

no you need to check your substitution and use the du/dx as myininaya showed

Answer 11

Hmm, okay.