280. Explanation of curvature; definition of curvature of a circle 281. Definition of radius of curvature and of circle of curvature. SECTION 2.-On evolutes referred to rectangular coordinates. SECTION 3.-Curvature of polar curves. SECTION 4.-Evolutes of polar curves. SECTION 1.-The theory of contact. 304. Contact depends on the number of consecutive points which 305. And therefore on the number of derived-functions which are equal at the point common to the two curves . . . . . . 306. Theorems deduced from the latter mode of considering 307. Two curves which have a common tangent intersect or not 331. The equations to a straight line and to a plane. . . . 334, 335. Modified forms of the equation to the tangent plane, SECTION 1.-Surfaces generated by straight lines. |