4.* Let u be a harmonic function in R" and suppose that lu(x)/*dx < oo. R" Show that u = 0. (Hint: Write the mean value property in a ball of radius r and use the Cauchy- Schwarz inequality given in Question 3.)

Advanced Engineering Mathematics
10th Edition
ISBN:9780470458365
Author:Erwin Kreyszig
Publisher:Erwin Kreyszig
Chapter2: Second-order Linear Odes
Section: Chapter Questions
Problem 1RQ
icon
Related questions
Question

please help Q4

4.* Let u be a harmonic function in R" and suppose that
lu(x)/*dx < oo.
R"
Show that u = 0. (Hint: Write the mean value property in a ball of radius r and use the Cauchy-
Schwarz inequality given in Question 3.)
Transcribed Image Text:4.* Let u be a harmonic function in R" and suppose that lu(x)/*dx < oo. R" Show that u = 0. (Hint: Write the mean value property in a ball of radius r and use the Cauchy- Schwarz inequality given in Question 3.)
3. Let U C R" and u, v e L²(U). Prove the Cauchy-Schwarz inequality,
u(х)u(х) dx| <
|u(x)/² dx
(Hint: Let A := (u, v)/({v, v)) and note that ||u – Av||² > 0.)
Transcribed Image Text:3. Let U C R" and u, v e L²(U). Prove the Cauchy-Schwarz inequality, u(х)u(х) dx| < |u(x)/² dx (Hint: Let A := (u, v)/({v, v)) and note that ||u – Av||² > 0.)
Expert Solution
steps

Step by step

Solved in 2 steps with 1 images

Blurred answer
Recommended textbooks for you
Advanced Engineering Mathematics
Advanced Engineering Mathematics
Advanced Math
ISBN:
9780470458365
Author:
Erwin Kreyszig
Publisher:
Wiley, John & Sons, Incorporated
Numerical Methods for Engineers
Numerical Methods for Engineers
Advanced Math
ISBN:
9780073397924
Author:
Steven C. Chapra Dr., Raymond P. Canale
Publisher:
McGraw-Hill Education
Introductory Mathematics for Engineering Applicat…
Introductory Mathematics for Engineering Applicat…
Advanced Math
ISBN:
9781118141809
Author:
Nathan Klingbeil
Publisher:
WILEY
Mathematics For Machine Technology
Mathematics For Machine Technology
Advanced Math
ISBN:
9781337798310
Author:
Peterson, John.
Publisher:
Cengage Learning,
Basic Technical Mathematics
Basic Technical Mathematics
Advanced Math
ISBN:
9780134437705
Author:
Washington
Publisher:
PEARSON
Topology
Topology
Advanced Math
ISBN:
9780134689517
Author:
Munkres, James R.
Publisher:
Pearson,