I. Let f : R → R be a continuous function. Show that ER sup is a Fo set
Let the function f: (a, b) → R is continuous in (a, b). If sup {f(x): x ∈ (a, b)} = L> 0 and inf {f(x): x ∈ (a, b)} = M <0, then prove that there is a c ∈ (a , b) such that f (c) = 0.
2 er Let I be an interval of R, and define the function f :I→ R by f(x) 1 +e2z or every z EZ. (a) Find the largest interval T where f is strictly increasing. (b) For this interval Z, determine the range f(T) (c) Let T- f(I). Show that the function f : I -» T is injective and surjective. (d) Determine the inverse function f-i : T → 1. (e) Verify that (fo f-1)()-y for every y E...
12. Let M be the set of continuous functions on R which vanish outside a finite interval (the interval may depend on the function). (a) Show that M is a metric space in the sup norm. (b) Show that M is not complete. Chapter 5. Sequences of Function 210 (C) Show that C.(R), the continuous functions which go to zero et is complete in the sup norm (problem 10 of Section 5.3). (d) Prove that Mis dense in Co(R). T...
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)...
Answer C 6. Let f be a continuous function on [0, oo) such that 0 f(z) Cl- for some C,e> 0, and let a = fo° f(x) da. (The estimate on f implies the convergence of this integral.) Let fk(x) = kf(ka) a. Show that lim00 fk(x) = 0 for all r > 0 and that the convergence is uniform on [8, oo) for any 6> 0. b. Show that limk00 So ()dz = a. c. Show that lim00 So...
th 5. (14pt) A function defined on D C R is said to be somewhat continuous if for any e >1, (51) Prove or find a counter example for the statement "a somewhat continuous func- (52) Let EC Rm, f: ER, and a e E. Prove or disprove that f is continuous at a there is a 6 0 such that whenever z,y D and la -vl <6, then f()-)e es tion is continuous." if and only if given any...
4. Let S be the set of continuous function f: [0;1) ! R. Let R be the relation defined on S by (f; g) 2 Rif(x) is O(g(x)). (a) Is R reflexive? (b) Is R antisymmetric? (c) is R symmetric? (d) is R transitive? Explain your answer in details. Use the definition of big-O to justify your answer if you think R has a certain property or give a counter example if you think R does not have a certain...
I need to answer 1b 2.5. Let f be a real valued function continuous on a closed, bounded Theorem set S. Then there exist x1,X2 S such that f(x1) S f(x) s f(x2) for all x e S. Proor. We recall that if T E' is bounded and closed, then y, - inf T and sup T are points of T (Example 4, Section 1.4). Let T- fIS. By Theorem 2.4, T is closed and bounded. Take x, such that...
Let f be a differentiable function on R. Assume f' is continuous and always positive. You are searching for a root of f using Newton's method (see Tutorial 5). Your first guess is Xo ER and you compute subsequent guesses as follows: In EN, 2n+1 = In - f(2n) f'(x Let & E R. Prove that IF {Xn}"-o converges to & THEN x is a root of f.
C(10.1]) be the set of continuous functions f : lo. 11 → R 5) Let R from the interval [0, 1] to the real numbers. For any number ce [0, 1] (a) Show that the set R is a ring and that the set Ic is an ideal of R. (b) Is I UI2 and ideal? Is I, nI an ideal? C(10.1]) be the set of continuous functions f : lo. 11 → R 5) Let R from the interval...