here G denotes the graph of f.
Problem I. Let f: R -> R be any map and suppose that the graph Tf CR is closed and connected. Show that f is continu...
Let R be an interval (open, closed, neither are all fine) and let f: I-> R be a continuous strictly increasing function. Do the following: (1) Show that the inverse function f -1 exists. (2) Prove that f is an open map (in the relative topology on I) (3) Prove that f1 is continuous
Let R be an interval (open, closed, neither are all fine) and let f: I-> R be a continuous strictly increasing function. Do the following: (1)...
5. Let R be equipped with the Fort topology TFp, defined by TF,-(U C R l p ¢ U or R-U is finite), with pER a point. (i) Is (R, (i) Is (R, TFp) path-connected? TF) connected?
5. Let R be equipped with the Fort topology TFp, defined by TF,-(U C R l p ¢ U or R-U is finite), with pER a point. (i) Is (R, (i) Is (R, TFp) path-connected? TF) connected?
I. Let f : R → R be a continuous function. Show that ER sup is a Fo set
I. Let f : R → R be a continuous function. Show that ER sup is a Fo set
Problem 6. Let Coo(R) denote the vector space of functions f : R → R such that f is infinitely differentiable. Define a function T: C (RCo0 (R) by Tf-f -f" a) Prove that T is a linear map b) Find a two-dimensional subspace of null(T).
2. Let f R R and g R-R be functions that are continuous on1,1 and differentiable on (1,1). Suppose that f(-1-f(1) and 9(-1). Show that there exists c e (1,1) such that
2. Let f R R and g R-R be functions that are continuous on1,1 and differentiable on (1,1). Suppose that f(-1-f(1) and 9(-1). Show that there exists c e (1,1) such that
1 Let f: R R be a continuously differentiable map satisfying ilf(x)-FG) ll 리1x-vil, f Rn. Then fis onto 2. f(RT) is a closed subset of R'" 3, f(R") is an open subset of RT 4. f(0)0 or all x, y E 5) S= (xe(-1,4] Sin(x) > 0). Let of the following is true? I. inf (S).< 0 2. sup (S) does not exist Which . sup (S) π ,' inf (S) = π/2
1 Let f: R R be...
(7) Let R= {f [0,1] - R | f continuous} be the ring of all continuous functions from the interval [0,1] to the real numbers. (a) For cE [0, 1, prove that Me := {feR | f(c) = 0} is a maximal ideal of R. Hint: consider the evaluation map ec- (b) Show that if M is any maximal ideal of R then there exists a cE [0,1 such that M = Me. Hint: show that any maximal ideal M...
Question 4* (Similar to 18.1) Suppose f is a continuous function on a closed interval [a, b]. In class, we proved that f attains its maximum on that interval, i.e. there exists Imar E la, so that f(Imar) > f(x) for all r E (a,b]. We didn't prove that f attains its minimum on the interval, but I claimed that the proof is similar. In fact, you can use the fact that f attains its maximum on any closed interval...
problem1&2 thx!
interval in R is a set IC R such that for all <y < z in R, if E I and z e I then Recall that an points yE I. We call an interval non-degenerate if it contains at least two (1) Let I be a nondegenerate interval in R, and suppose f: IR is continuous (a) Show that f[] is an interval in R. (b) Show that if I is closed and bounded, then so is...
Problem 4 (4 points each). Let S = R {0}. (a) Let f: S R be f(x) = cos(1/x). Show that lim-0 f(x) does not exist. (b) For any fixed a > 0, let f: S+R be f(x) = rºcos(1/x). Show that lim -- f(x) = 0. (c) Find a value be R for which the function f: R+R given by f(x) = { 2" cos(1/x) if r +0, if x = 0, is continuous at 0. Is this b...