Let f : X → Y and suppose that B is an arbitrary subset of Y . Show that f(inverse) f^-1 [Y \ B] = X \ f^-1 [B].

Let X and Y be sets, A is a subset of X. Define functions f: A --> Y and F: X --> Y. Show that F is an extension of f if and only if the graph of f is a subset of the graph of F.
9. Let X and Y be metric spaces, and let D be a dense subset of X. (For the definition of "dense, see Problem 4 at the end of Section 3.5.) (a) Let f : X → Y and g : X → Y be continuous functions. Suppose that f(d)gld) for all d E D. Prove that f and g are the same function.
Question4 please
(1). Let f: Z → Z be given by f(x) = x2. Find F-1(D) where (a) D = {2,4,6,8, 10, 12, 14, 16}. (b) D={-9, -4,0, 16, 25}. (c) D is the set of prime numbers. (d) D = {2k|k Ew} (So D is the set of non-negative integer powers of 2). (2). Suppose that A and B are sets, C is a proper subset of A and F: A + B is a 1-1 function. Show that...
If A and B are sets and f : A → B, then for any subset S of A we define f(S) {be B : b-f(a) for some a ε S). Similarly, for any subset T of B we define the pre-image of T as Note that f (T) is well defined even if f does not have an inverse! Now let fRR be defined as f(x) 2. Let Si denote the closed interval [-2,1], that is all TE R...
2. Let U be an open subset of R and let A be a compact subset of U. Suppose that f: U R is a iction of class C() aud let F-(()e KIf(r, y) 0 and that Df does not vatish on E. Investigate whether Dis a Jordan region. annc
Let h : X −→ Y be defined by
h(x) :=
f(x) if x ∈ F
g
−1
(x) if x ∈ X − F
Now we must prove that h is injective and bijective. Starting
with injectivity, let x1, x2 ∈
X such that h(x1) = h(x2). Assume x1 ∈ F and x2 ∈ X −F. Then h(x1)
= f(x1) ∈ f(F)
and h(x2) = g
−1
(x2) ∈ g
−1
(X − F) = Y...
4. Let f(x, y) = (xy, r2 + y). Note that f(1, 2) = (2,5). (a) Show that has a smooth inverse f-1 in a neighborhood of the point (1,2). (b) Find the differential matrix D(-)(2,5).
Example: Let x, y ∈ Rn, where n ∈ N. The line segment joining x to y is the subset {(1 − t)x + ty : 0 ≤ t ≤ 1 } of R n . A subset A of Rn, where n ∈ N, is called convex if it contains the line segment joining any two of its points. It is easy to check that any convex set is path-connected. (a) Let f : X → Y be an...
Suppose that f :X + Y is a surjection and let yo e Y. Define Z = X -f({yo}) (a) Show that the function g: 2 + Y - {yo}, given by g(x) = f(x) for xe Z, well-defined function. (b) Show that g is a surjection. That denotes
7. Let A be a 4 x 3 matrix, and let b and y be two arbitrary vectors in R. We are told that the system Ax- b has a unique solution. What can you say about the number of solutions of the system Ax - y? Explain your answer. 8. Let u. v, w, b be arbitrary vectors in R". Suppose that b = x1u+xy+23w for some scalars i, r23. Show that Span u, v, w, b Span u,...