| 词汇 | directrix |
| 释义 | BETA Examples of directrixdirectrix isn’t in the Cambridge Dictionary yet. You can help! A circular cone has a directrix that is a circle. Measured along the axis of symmetry, the vertex is the midpoint between the focus and the directrix. From Wikipedia This example is from Wikipedia and may be reused under a CC BY-SA license. Other examples are a conical surface with elliptical directrix, the right conoid, the helicoid, and the tangent developable of a smooth curve in space. From Wikipedia This example is from Wikipedia and may be reused under a CC BY-SA license. The broken line is the "directrix" of the surface; the parallel lines are its "generators" (or "elements"). From Wikipedia This example is from Wikipedia and may be reused under a CC BY-SA license. The parabola is the locus of points in that plane that are equidistant from both the directrix and the focus. From Wikipedia This example is from Wikipedia and may be reused under a CC BY-SA license. In the following proof, the fact that every point on the parabola is equidistant from the focus and from the directrix is taken as axiomatic. From Wikipedia This example is from Wikipedia and may be reused under a CC BY-SA license. For the parabola, the center of the directrix moves to the point at infinity (see projective geometry). From Wikipedia This example is from Wikipedia and may be reused under a CC BY-SA license. The focal parameter ("p") is the distance from the focus (or one of the two foci) to the directrix. From Wikipedia This example is from Wikipedia and may be reused under a CC BY-SA license. Conversely, two tangents which intersect on the directrix are perpendicular. From Wikipedia This example is from Wikipedia and may be reused under a CC BY-SA license. The dashed blue line is the directrix of the ellipse shown. From Wikipedia This example is from Wikipedia and may be reused under a CC BY-SA license. The ellipse thus generated has its second focus at the center of the directrix circle, and the ellipse lies entirely within the circle. From Wikipedia This example is from Wikipedia and may be reused under a CC BY-SA license. Later uses, along with equidistant and directrix, are vague and metaphorical. From Wikipedia This example is from Wikipedia and may be reused under a CC BY-SA license. The "x" -axis thus chosen is called the "directrix" of the catenary. From Wikipedia This example is from Wikipedia and may be reused under a CC BY-SA license. The envelope of the directrix of the parabola is also a catenary. From Wikipedia This example is from Wikipedia and may be reused under a CC BY-SA license. One description of a parabola involves a point (the focus) and a line (the directrix). From Wikipedia This example is from Wikipedia and may be reused under a CC BY-SA license. A parabola has a single axis of reflective symmetry, which passes through its focus and is perpendicular to its directrix. From Wikipedia This example is from Wikipedia and may be reused under a CC BY-SA license. The focus does not lie on the directrix. From Wikipedia This example is from Wikipedia and may be reused under a CC BY-SA license. As another example, a sideways parabola (one whose directrix is a vertical line) is not the graph of a function because some vertical lines will intersect the parabola twice. From Wikipedia This example is from Wikipedia and may be reused under a CC BY-SA license. In one solution of the former problem is the first recorded use of the property of a conic (a hyperbola) with reference to the focus and directrix. From Wikipedia This example is from Wikipedia and may be reused under a CC BY-SA license. |
反思网英语在线翻译词典收录了377474条英语词汇在线翻译词条，基本涵盖了全部常用英语词汇的中英文双语翻译及用法，是英语学习的有利工具。