Recent content by kbgregory

  1. K

    Suppose that f is continuous on (0,1) and that int[0,x] f = int[x,1] f

    Ok, I just found out from my professor that there is a typo in the problem, and that f is continuous on [0,1], so I think I can take it from here.
  2. K

    Suppose that f is continuous on (0,1) and that int[0,x] f = int[x,1] f

    Homework Statement Suppose that f is continuous on (0,1) and that int[0,x] f = int[x,1] f for all x in [0,1]. Prove that f(x)=0 for all x in [0,1]. Homework Equations We know that since f is continuous on (0,1), F(x) = int[0,x] f and F'(x) = f(x) for x in (0,1). The Attempt...
  3. K

    Show f(x) = { x/2 if x rational , x if x irrational is not differentiable at 0

    Homework Statement Show that the function f(x) = { x/2 if x is rational { x if x irrational is not differentiable at 0 Homework Equations If f is differentiable at 0 then for every e > 0 there exists some d > 0 such that when |x| < d, |(f(x)-f(0))/x - L | < e...
  4. K

    If f is differentiable at x = a, evaluate lim[h->0] (f(a+2h)-f(a+3h))/h

    Homework Statement If f is differentiable at x = a, evaluate lim[h->0] (f(a+2h)-f(a+3h))/h Homework Equations We know that f'(a) = lim[h->0] (f(a+h)-f(a))/h The Attempt at a Solution I have done the following, and I am not sure if it is correct, though the result makes sense...
  5. K

    Passing the limit through the derivative of a differentiable function

    Homework Statement Suppose f is differentiable on an open interval I and let x* \in I. Show that there exists a sequence {x_n}\subset I such that lim[n->inf]{x_n}=x* and lim[n->inf]{f'(x_n)}=f'(x*). Homework Equations We know that a function g is continuous iff for any sequence...
  6. K

    For a continuous function on [0,2] , f(0)=f(2)

    Homework Statement Suppose f is a continuous function on [0,2] with f(0) = f(2). Show that there is an x in [0,1] where f(x) = f(x+1). Homework Equations By the Intermediate Value Theorem, we know that any values between sup{f(x)} and inf {f(x)} over x in [0,2] will be repeated...
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