hey guys,have a tough problem....any help would be great
Let f(x) be C∞ function and assume that ∃a > 0 such that such that f ′(a) f '(2a) < 0. Show that f(x) has a local extrema on (0,∞).
f ' meaning f prime
By the way, you titled this "constant infinity function".
You understand, do you not, that the "C" in $\displaystyle C^\infty$ means continuous, not "constant". Functions in $\displaystyle C^\infty$ are the functions, all of whose derivatives are continuous.