6. (14 pts) Let f :R→ R be a differentiable function. Suppose that 0 ≤ f' (x) ≤ f(x) for all c
. Show that g (x) =
is decreasing. If f vanishes at some point, conclude that f is identically zero.
6. (14 pts) Let f :R→ R be a differentiable function. Suppose that 0 ≤ f' (x) ≤ f(x) for all c
. Show that g (x) =
is decreasing. If f vanishes at some point, conclude that f is identically zero.