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  2. Evolute - Wikipedia

    en.wikipedia.org/wiki/Evolute

    From this equation one gets the following properties of the evolute: At points with ′ = the evolute is not regular. That means: at points with maximal or minimal curvature (vertices of the given curve) the evolute has cusps. (See the diagrams of the evolutes of the parabola, the ellipse, the cycloid and the nephroid.)

  3. Conic section - Wikipedia

    en.wikipedia.org/wiki/Conic_section

    Define b by the equations c 2 = a 2 − b 2 for an ellipse and c 2 = a 2 + b 2 for a hyperbola. For a circle, c = 0 so a 2 = b 2, with radius r = a = b. For the parabola, the standard form has the focus on the x-axis at the point (a, 0) and the directrix the line with equation x = −a. In standard form the parabola will always pass through the ...

  4. Parabola - Wikipedia

    en.wikipedia.org/wiki/Parabola

    In the theory of quadratic forms, the parabola is the graph of the quadratic form x 2 (or other scalings), while the elliptic paraboloid is the graph of the positive-definite quadratic form x 2 + y 2 (or scalings), and the hyperbolic paraboloid is the graph of the indefinite quadratic form x 2 − y 2. Generalizations to more variables yield ...

  5. Parabolic reflector - Wikipedia

    en.wikipedia.org/wiki/Parabolic_reflector

    However, in informal language, the word parabola and its associated adjective parabolic are often used in place of paraboloid and paraboloidal. [ 2 ] If a parabola is positioned in Cartesian coordinates with its vertex at the origin and its axis of symmetry along the y-axis, so the parabola opens upward, its equation is 4 f y = x 2 {\textstyle ...

  6. Orthoptic (geometry) - Wikipedia

    en.wikipedia.org/wiki/Orthoptic_(geometry)

    In the case of an ellipse ⁠ x 2 / a 2 ⁠ + ⁠ y 2 / b 2 ⁠ = 1 one can adopt the idea for the orthoptic for the quadratic equation + = Now, as in the case of a parabola, the quadratic equation has to be solved and the two solutions m 1 , m 2 must be inserted into the equation tan 2 ⁡ α = ( m 1 − m 2 1 + m 1 m 2 ) 2 . {\displaystyle ...

  7. Semi-major and semi-minor axes - Wikipedia

    en.wikipedia.org/wiki/Semi-major_and_semi-minor_axes

    where (h, k) is the center of the ellipse in Cartesian coordinates, in which an arbitrary point is given by (x, y). The semi-major axis is the mean value of the maximum and minimum distances r max {\displaystyle r_{\text{max}}} and r min {\displaystyle r_{\text{min}}} of the ellipse from a focus — that is, of the distances from a focus to the ...

  8. Universal parabolic constant - Wikipedia

    en.wikipedia.org/wiki/Universal_parabolic_constant

    The universal parabolic constant is the red length divided by the green length. The universal parabolic constant is a mathematical constant.. It is defined as the ratio, for any parabola, of the arc length of the parabolic segment formed by the latus rectum to the focal parameter.

  9. Involute - Wikipedia

    en.wikipedia.org/wiki/Involute

    In mathematics, an involute (also known as an evolvent) is a particular type of curve that is dependent on another shape or curve. An involute of a curve is the locus of a point on a piece of taut string as the string is either unwrapped from or wrapped around the curve.