EXERCISE 4.19. Let S be a path-connected oriented regular surface. If all points of S are umbilical points, prove that S is contained in either a plane or a sphere.

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
EXERCISE 4.19. Let S be a path-connected oriented regular surface. If
all points of S are umbilical points, prove that S is contained in either a plane
or a sphere.
HINT: First prove that the principal curvature function k = k1 = k2 is
constant on S. For this, let o : UC R? – VCS be a coordinate chart. At
every q E U, Nu(q) = dNo(g)(0u(q)) = -k(q) · ou(q). That is, Nu = -k · ou
on all of U, and similarly, N, = -k.o, on all of U. Differentiating this first
equation with respect to v and the second with respect to u and subtracting
yields kuou = k,őv, which implies that ku = ky = 0; thus, k is constant. If
k + 0, demonstrate that the point o+N is constant on U, so V is contained
in the sphere of radius about this point.
%3D
%3D
Transcribed Image Text:EXERCISE 4.19. Let S be a path-connected oriented regular surface. If all points of S are umbilical points, prove that S is contained in either a plane or a sphere. HINT: First prove that the principal curvature function k = k1 = k2 is constant on S. For this, let o : UC R? – VCS be a coordinate chart. At every q E U, Nu(q) = dNo(g)(0u(q)) = -k(q) · ou(q). That is, Nu = -k · ou on all of U, and similarly, N, = -k.o, on all of U. Differentiating this first equation with respect to v and the second with respect to u and subtracting yields kuou = k,őv, which implies that ku = ky = 0; thus, k is constant. If k + 0, demonstrate that the point o+N is constant on U, so V is contained in the sphere of radius about this point. %3D %3D
Expert Solution
steps

Step by step

Solved in 2 steps

Blurred answer
Knowledge Booster
Double Integration
Learn more about
Need a deep-dive on the concept behind this application? Look no further. Learn more about this topic, advanced-math and related others by exploring similar questions and additional content below.
Similar questions
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,