What is the inverse of #y=-e^-x#?

What is the inverse of #y=-e^-x#?

1 Answer
Dec 19, 2017

Please see below.

Explanation:

The inverse function of #f(x) = -e^-x# is found by solving for #x#

#y = -e^-x#

#-y=e^-x#

#-x=ln(-y)#

#x = -ln(-y)#

So #f^-1(x) = -ln(-x)# #" "# (Domain is #x < 0#)

Note that the compositions are the composition identities #id(x) = x# on the domains.

#f(f^-1(x)) = x# and #f^-1(f(x)) = x#

The additive inverse is #e^-x# because #(-e^-x)+ e^-x = 0# (the additive identity)

The multiplicative inverse is #-e^x# because (-e^-x) * -e^x = 1# (the multiplicative identity)