Let f(x) be continuous on [a,b] and differentiable on (a,b).
Number of correct statements among the following:
Statement I: If f(x) is strictly increasing on (a,b), then f1(x)>0 for all x∈(a,b).
Statement II: If f(x) is strictly decreasing on (a,b), then f1(x)<0 for all x∈(a,b).
Statement III: f(x) and f1(x) have opposite sign, for all x, then f2(x) is a decreasing function.
Statement IV: f(x) and f1(x) have opposite sign, for all x, then |f(x)| is an increasing function.
(2)
Statement-II: f(x)=-x3 at x=0 contradiction
Statement-III: (f2(x))1=2f(x)f'(x)=-ve
Statement-IV: