Question

Let f(x) = |5+9x|
then for x < -5/9, f '(x) = ?
the left hand derivative of f(x) at x= -5/9 is ?
the right hand derivative of f(X) at x= -5/9 is ?

Answer 1

at x=-5/9 is vertex of this absolute value graph, x>-5/9 have positive slope and x<-5/9 have negative slope
f'(x) = -9, since x<-5/9
this is the left hand derivative as well
the right hand derivative is +9

Answer 2

since there are 2 possible answers, technically f'(-5/9) does not exist

Answer 3

awesome. thanks again, man.

Answer 4

your welcome :)