I'm been having some problems with these and I really need the help

1) The number of inflection points for the graph of

y=2x+cos(x^2) in the interval 0≤x≤5 is

the answer is 8

2) If f(x) = 2x^2 -x^3 and g(x) = x^2-2x, for what values of a and b is

the integral from a to b f(x) dx > the integral from a to b g(x) dx?

The answer is a=0 and b=2

3)Also what does the lim as h approaches 0 when f(2+h)-f(2)/h=2 look like? Or rather what does it do.