Question

EXERCISE 4.16. Prove that every compact regular surface has a point of positive Gaussian curvature. HINT: LetpES be a point of maximum distance to the origin. By applying Exercise 1.43 on page 32 to a normal section, conclude that the normal cur- vature of S at p in every direction is where r is the distance from p to the origin. EXERCISE 1.43 Let γ: 1 → Rn be a regular curve. Assume that the function t Iy(t) has a local maximum value of r occurring at time to Prove that Is there any upper bound for R(to) under these conditions?

Answer 1

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