19.02.2013 Views

Blaga P. Lectures on the differential geometry of - tiera.ru

Blaga P. Lectures on the differential geometry of - tiera.ru

Blaga P. Lectures on the differential geometry of - tiera.ru

SHOW MORE
SHOW LESS

You also want an ePaper? Increase the reach of your titles

YUMPU automatically turns print PDFs into web optimized ePapers that Google loves.

6 C<strong>on</strong>tents<br />

1.10.1 The geometrical meaning <strong>of</strong> <strong>the</strong> torsi<strong>on</strong> . . . . . . . . . . . . . 53<br />

1.10.2 Some fur<strong>the</strong>r applicati<strong>on</strong>s <strong>of</strong> <strong>the</strong> Frenet formulae . . . . . . . . 54<br />

1.10.3 General helices. Lancret’s <strong>the</strong>orem . . . . . . . . . . . . . . . 56<br />

1.10.4 Bertrand curves . . . . . . . . . . . . . . . . . . . . . . . . . . 58<br />

1.11 The local behaviour <strong>of</strong> a parameterized curve around a biregular point . 62<br />

1.12 The c<strong>on</strong>tact between a space curve and a plane . . . . . . . . . . . . . 64<br />

1.13 The c<strong>on</strong>tact between a space curve and a sphere. The osculating sphere 66<br />

1.14 Existence and uniqueness <strong>the</strong>orems for parameterized curves . . . . . . 68<br />

1.14.1 The behaviour <strong>of</strong> <strong>the</strong> Frenet frame under a rigid moti<strong>on</strong> . . . . . 68<br />

1.14.2 The uniqueness <strong>the</strong>orem . . . . . . . . . . . . . . . . . . . . . 70<br />

1.14.3 The existence <strong>the</strong>orem . . . . . . . . . . . . . . . . . . . . . . 72<br />

2 Plane curves 75<br />

2.1 Introducti<strong>on</strong> . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75<br />

2.2 Envelopes <strong>of</strong> plane curves . . . . . . . . . . . . . . . . . . . . . . . . 75<br />

2.2.1 Curves given through an implicit equati<strong>on</strong> . . . . . . . . . . . . 77<br />

2.2.2 Families <strong>of</strong> curves depending <strong>on</strong> two parameters . . . . . . . . 79<br />

2.2.3 Applicati<strong>on</strong>s: <strong>the</strong> evolute <strong>of</strong> a plane curve . . . . . . . . . . . . 79<br />

2.3 The curvature <strong>of</strong> a plane curve . . . . . . . . . . . . . . . . . . . . . . 81<br />

2.3.1 The geometrical interpretati<strong>on</strong> <strong>of</strong> <strong>the</strong> signed curvature . . . . . 84<br />

2.4 The curvature center. The evolute and <strong>the</strong> involute <strong>of</strong> a plane curve . . . 86<br />

2.5 The osculating circle <strong>of</strong> a curve . . . . . . . . . . . . . . . . . . . . . . 91<br />

2.6 The existence and uniqueness <strong>the</strong>orem for plane curves . . . . . . . . . 92<br />

3 The integrati<strong>on</strong> <strong>of</strong> <strong>the</strong> natural equati<strong>on</strong>s <strong>of</strong> a curve 95<br />

3.1 The Riccati equati<strong>on</strong> associated to <strong>the</strong> natural equati<strong>on</strong>s <strong>of</strong> a curve . . . 95<br />

3.2 Examples for <strong>the</strong> integrati<strong>on</strong> <strong>of</strong> <strong>the</strong> natural equati<strong>on</strong> <strong>of</strong> a plane curve . . 96<br />

Problems 103<br />

II Surfaces 113<br />

4 General <strong>the</strong>ory <strong>of</strong> surfaces 115<br />

4.1 Parameterized surfaces (patches) . . . . . . . . . . . . . . . . . . . . . 115<br />

4.2 Surfaces . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 116<br />

4.2.1 Representati<strong>on</strong>s <strong>of</strong> surfaces . . . . . . . . . . . . . . . . . . . . 116<br />

4.3 The equivalence <strong>of</strong> local parameterizati<strong>on</strong>s . . . . . . . . . . . . . . . . 119<br />

4.4 Curves <strong>on</strong> a surface . . . . . . . . . . . . . . . . . . . . . . . . . . . . 122

Hooray! Your file is uploaded and ready to be published.

Saved successfully!

Ooh no, something went wrong!