Posted by Brandon on .
Show that f is strictly monotonic on the given interval and therefore has an inverse function on that interval.
f(x) = abs. val. (x + 2), [2, infinity)

Calc 
MathMate,
Please do not change screennames. It is easier for Erica/Brandon because reference can be made to a previous problem.
http://www.jiskha.com/display.cgi?id=1291619172
For this problem, you do not need to find f'(x), because it consists of two straight lines that intersect. A single straight line is monotonic if it is not horizontal.
Treat f(x) as two separate parts:
f(x)=(x+2) if x<2, and
f(x)=x+2 if x≥2.
So if the domain is given in [2,∞], it consists of a straight line and therefore has an inverse.
Follow the steps set out in your previous question to find the inverse, if necessary, or as practice.
http://www.jiskha.com/display.cgi?id=1291623706