Search results
Results from the WOW.Com Content Network
An ellipse (red) obtained as the intersection of a cone with an inclined plane. Ellipse: notations Ellipses: examples with increasing eccentricity. In mathematics, an ellipse is a plane curve surrounding two focal points, such that for all points on the curve, the sum of the two distances to the focal points is a constant.
An ellipse has two axes and two foci. Unlike most other elementary shapes, such as the circle and square, there is no algebraic equation to determine the perimeter of an ellipse. Throughout history, a large number of equations for approximations and estimates have been made for the perimeter of an ellipse.
Given: Ellipsoid x 2 / a 2 + y 2 / b 2 + z 2 / c 2 = 1 and the plane with equation n x x + n y y + n z z = d, which have an ellipse in common. Wanted: Three vectors f 0 (center) and f 1 , f 2 (conjugate vectors), such that the ellipse can be represented by the parametric equation
The equation is for an ellipse, since both eigenvalues are positive. (Otherwise, if one were positive and the other negative, it would be a hyperbola.) The principal axes are the lines spanned by the eigenvectors. The minimum and maximum distances to the origin can be read off the equation in diagonal form.
Given the curve y 2 = x 3 + bx + c over the field K (whose characteristic we assume to be neither 2 nor 3), and points P = (x P, y P) and Q = (x Q, y Q) on the curve, assume first that x P ≠ x Q (case 1). Let y = sx + d be the equation of the line that intersects P and Q, which has the following slope: =
The eccentricity of an ellipse is strictly less than 1. When circles (which have eccentricity 0) are counted as ellipses, the eccentricity of an ellipse is greater than or equal to 0; if circles are given a special category and are excluded from the category of ellipses, then the eccentricity of an ellipse is strictly greater than 0.
The first degree polynomial equation = + is a line with slope a. A line will connect any two points, so a first degree polynomial equation is an exact fit through any two points with distinct x coordinates. If the order of the equation is increased to a second degree polynomial, the following results:
Eliminating p, q, r, and λ from these equations, along with Xp + Yq + Zr = 0, gives the equation in X, Y and Z of the dual curve. On the left: the ellipse ( x / 2 ) 2 + ( y / 3 ) 2 = 1 with tangent lines xX + yY = 1 for any X, Y, such that (2X) 2 + (3Y) 2 = 1. On the right: the dual ellipse (2X) 2 + (3Y) 2 = 1. Each tangent to the ...