Originally Posted by
skybluesea2010 I appreciate if you can help me guys with any of these problems. They are good for practice and review of derivatives.
Problem 1:
Let f(x) be a real valued function defined for all x >= 1, that satisfies
f(1) = 1 and
f'(x) = 1/[x^2 + (f(x))^2]
Prove that lim f(x) as x tends to infinity exists and is less than 1+ pi/4.
Problem 2:
Suppose that a continuously differentiable function f : IR --IR satisfies
f'(x) = g(f(x)) + h(x) for x in IR,
where the functions g, h : IR ---IR are C 00 (i.e. infinitely differentiable). Prove that
the function f is infinitely differentiable as well.
problem 3:
Prove that if f : [0,1)--- IR is nonnegative, integrable, and uniformly
continuous, then lim f(x) =0 as x tends to 00.
Problem 4:
Suppose that a differentiable function f : IR ---IR and its derivative f'
have no common zeros. Prove that f has only finitely many zeros in [0, 1].
Problem 5:
Suppose that f : [0,1)---IR is continuous on [0,1), differentiable on
(0,00), f(0) = 0, and lim f(x) = 0 as x tends to 00. Prove that there exists a point c in (0,00) such
that f'(c) = 0.