(Complex Analysis) Prove the following maximum principle for harmonic functions: Let u be harmoni...
(Complex Analysis) Prove the following maximum principle for harmonic functions: Let u be harmonic in a bounded domain E and continuous in E ∪ dE. Then max(x, y)E E U dE u= sup(x, y)E E U dE u; min(x, y)E E U dE u= inf(x, y)E E U dE u. (Not the first E after the subscript (x, y) denotes element of, and the next on is the domain and the next is the derivative of the domain.)
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(Complex Analysis) Prove the following maximum principle for harmonic functions: Let u be harmoni...
Problem 3. (1) Let H be a Hilbert space and S, TE B(HH). Then, prove that...
Problem 3. (1) Let H be a Hilbert space and S, TE B(HH). Then, prove that ||ST|| ||||||||| (2) Let X, Y be Hilbert spaces and Te B(X,Y). Then, prove that ||1||| sup ||T3|1 TEX=1 Let X, Y be Banach spaces. Definition (review) We denote by B(X, Y) a set of all bounded linear operators T:X + Y with D(T) = X. B(X, Y) is a vector space. Definition (review) A linear operator T:X + Y is said to be...
Problem 3 (12 points): Let D be a bounded domain in R" with smooth boundary. Suppose that K(x, y) is a Green's function for the Neumann . For each x E D, the function y H K(x, y) is a smooth...
Problem 3 (12 points): Let D be a bounded domain in R" with smooth boundary. Suppose that K(x, y) is a Green's function for the Neumann . For each x E D, the function y H K(x, y) is a smooth harmonic For each x E D, the normal derivative of the function y K(x, y) . For each z e D, the function y K(x,y)-Г(z-y) is smooth near problem. This means the following: function on D(r satisfies (VyK(x, y).v(b))-arefor...
Problem 5. For u = (Uk)x=1,2,... El, we set Tnu = (U1, U2, ..., Un, 0,...)....
Problem 5. For u = (Uk)x=1,2,... El, we set Tnu = (U1, U2, ..., Un, 0,...). (1) Prove that Tn E B(C2, (). (2) We define the operator I as Iu = u (u € 14). Then, prove that for any u ele, lim ||T,u - Tulee = 0. (3) Prove that I, does not converge to I with respect to the norm of B(C²,1). Let X, Y be Banach spaces. Definition (review) We denote by B(X, Y) a set...
7. Show that the following functions u(x, y) monic functions v(x, y) and determine f(z) = u(x,y) + iv(x, y) are harmoni...
7. Show that the following functions u(x, y) monic functions v(x, y) and determine f(z) = u(x,y) + iv(x, y) are harmonic, find their conjugate har- as functions of 2. 2x2 2лу — 5х — 22. Зл? — 8ху — Зу? + 2у, (а) и(х, у) (b) и(х, у) (с) и(х, у) (d) u(a, y) 2e cos y 3e" sin y, = 3e-* cos y + 5e-" sin y, = elx cos y - e y sin y, (e) u(x,...
complex analysis Let f(z) be continuous on S where for some real numbers 0< a <...
complex analysis
Let f(z) be continuous on S where for some real numbers 0< a < b. Define max(Re(z)Im(z and suppose f(z) dz = 0 S, for all r E (a, b). Prove or disprove that f(z) is holomorphic on S.
3. Let f, g : [a,b] → R be functions such that f is integrable, g is continuous, and g(x) >0 for ...
3. Let f, g : [a,b] → R be functions such that f is integrable, g is continuous, and g(x) >0 for all r E [a, b] Since both f,g are bounded, let K >0 be such that lf(z)| K and g(x) K for all x E [a3] (a) Let n > 0 be given. Prove that there is a partition P of [a, b such that U (P. f) _ L(P./) < η and Mi(P4)-mi(P4) < η for all...
Let f : [a, b] → R and xo e (a,b). Assume that f is continuous...
Let f : [a, b] → R and xo e (a,b). Assume that f is continuous
on [a,b] \{x0} and lim x approaches too x0 f(x) = L (L is finite)
exists. Show that f is Riemann integrable.
1. (20 pts) Let f : [a, b] R and to € (a,b). Assume that f is continuous on [a, b]\{ro} and limz-ro f (x) = L (L is finite) exists. Show that f is Riemann integrable. Hint: We split it into...
Question 1 1. [5 pts] Give a complete definition of lim f(x) = -oo if... 2....
Question 1
1. [5 pts] Give a complete definition of lim f(x) = -oo if... 2. [25 pts] Give an example of each of the following, or state one or more theorems which show that such an example is impossible: a. A countable collection of nonempty closed proper subsets of R whose union is open. b. A nonempty bounded subset of R with no cluster points. c. A convergent sequence with two convergent subsequences with distinct limits. d. A function...
I need to answer 1b 2.5. Let f be a real valued function continuous on a...
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...
(b) Let D C C be a regular domain, f : D → D' C C...
(b)
Let D C C be a regular domain, f : D → D' C C be a complex-valued function and f(z) = u(x,y) + iv(x,y). (a) Show that if/(z) is differentiable on D implies the Cauchy-Riemann equation, i.e., au dyJu on D. (b) Assume that D- f(D).e. fis a conformal mapping from domain D onto domain D. Le x' =a(x,y), y = r(x,y). Show that if φ(x,y) is harmonic on D. ie..知+Oy-0, then is also harmonic on domain D....
Problem 3. (1) Let H be a Hilbert space and S, TE B(HH). Then, prove that ||ST|| ||||||||| (2) Let X, Y be Hilbert spaces and Te B(X,Y). Then, prove that ||1||| sup ||T3|1 TEX=1 Let X, Y be Banach spaces. Definition (review) We denote by B(X, Y) a set of all bounded linear operators T:X + Y with D(T) = X. B(X, Y) is a vector space. Definition (review) A linear operator T:X + Y is said to be...
Problem 3 (12 points): Let D be a bounded domain in R" with smooth boundary. Suppose that K(x, y) is a Green's function for the Neumann . For each x E D, the function y H K(x, y) is a smooth harmonic For each x E D, the normal derivative of the function y K(x, y) . For each z e D, the function y K(x,y)-Г(z-y) is smooth near problem. This means the following: function on D(r satisfies (VyK(x, y).v(b))-arefor...
Problem 5. For u = (Uk)x=1,2,... El, we set Tnu = (U1, U2, ..., Un, 0,...). (1) Prove that Tn E B(C2, (). (2) We define the operator I as Iu = u (u € 14). Then, prove that for any u ele, lim ||T,u - Tulee = 0. (3) Prove that I, does not converge to I with respect to the norm of B(C²,1). Let X, Y be Banach spaces. Definition (review) We denote by B(X, Y) a set...
7. Show that the following functions u(x, y) monic functions v(x, y) and determine f(z) = u(x,y) + iv(x, y) are harmonic, find their conjugate har- as functions of 2. 2x2 2лу — 5х — 22. Зл? — 8ху — Зу? + 2у, (а) и(х, у) (b) и(х, у) (с) и(х, у) (d) u(a, y) 2e cos y 3e" sin y, = 3e-* cos y + 5e-" sin y, = elx cos y - e y sin y, (e) u(x,...
complex analysis
Let f(z) be continuous on S where for some real numbers 0< a < b. Define max(Re(z)Im(z and suppose f(z) dz = 0 S, for all r E (a, b). Prove or disprove that f(z) is holomorphic on S.
3. Let f, g : [a,b] → R be functions such that f is integrable, g is continuous, and g(x) >0 for all r E [a, b] Since both f,g are bounded, let K >0 be such that lf(z)| K and g(x) K for all x E [a3] (a) Let n > 0 be given. Prove that there is a partition P of [a, b such that U (P. f) _ L(P./) < η and Mi(P4)-mi(P4) < η for all...
Let f : [a, b] → R and xo e (a,b). Assume that f is continuous
on [a,b] \{x0} and lim x approaches too x0 f(x) = L (L is finite)
exists. Show that f is Riemann integrable.
1. (20 pts) Let f : [a, b] R and to € (a,b). Assume that f is continuous on [a, b]\{ro} and limz-ro f (x) = L (L is finite) exists. Show that f is Riemann integrable. Hint: We split it into...
Question 1
1. [5 pts] Give a complete definition of lim f(x) = -oo if... 2. [25 pts] Give an example of each of the following, or state one or more theorems which show that such an example is impossible: a. A countable collection of nonempty closed proper subsets of R whose union is open. b. A nonempty bounded subset of R with no cluster points. c. A convergent sequence with two convergent subsequences with distinct limits. d. A function...
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...
(b)
Let D C C be a regular domain, f : D → D' C C be a complex-valued function and f(z) = u(x,y) + iv(x,y). (a) Show that if/(z) is differentiable on D implies the Cauchy-Riemann equation, i.e., au dyJu on D. (b) Assume that D- f(D).e. fis a conformal mapping from domain D onto domain D. Le x' =a(x,y), y = r(x,y). Show that if φ(x,y) is harmonic on D. ie..知+Oy-0, then is also harmonic on domain D....
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