Search results
Results From The WOW.Com Content Network
The generation of a bicylinder Calculating the volume of a bicylinder. A bicylinder generated by two cylinders with radius r has the volume =, and the surface area [1] [6] =.. The upper half of a bicylinder is the square case of a domical vault, a dome-shaped solid based on any convex polygon whose cross-sections are similar copies of the polygon, and analogous formulas calculating the volume ...
The counterexamples are equirectangular and equal-area cylindrical projections (of normal aspects). These projections expand meridian-wise and parallel-wise by different ratios respectively. Thus, parallels and meridians cross rectangularly on the map, but these projections do not preserve other angles; i.e. these projections are not conformal.
In plane geometry there are three types of angles that may be preserved in a conformal map. [3] Each is hosted by its own real algebra, ordinary complex numbers, split-complex numbers, and dual numbers. The conformal maps are described by linear fractional transformations in each case. [4]
If the elements of the cylinder are perpendicular to the planes containing the bases, the cylinder is a right cylinder, otherwise it is called an oblique cylinder. If the bases are disks (regions whose boundary is a circle) the cylinder is called a circular cylinder. In some elementary treatments, a cylinder always means a circular cylinder. [2]
Vectors are defined in cylindrical coordinates by (ρ, φ, z), where . ρ is the length of the vector projected onto the xy-plane,; φ is the angle between the projection of the vector onto the xy-plane (i.e. ρ) and the positive x-axis (0 ≤ φ < 2π),
The formulae presume a spherical model and use these definitions: [3] λ is the longitude; λ 0 is the central meridian; φ is the latitude; φ 0 is the standard latitude; S is the stretch factor; x is the horizontal coordinate of the projected location on the map; y is the vertical coordinate of the projected location on the map
In two dimensions, every conformal metric is locally conformally flat. In dimension n > 3 a conformal metric is locally conformally flat if and only if its Weyl tensor vanishes; in dimension n = 3, if and only if the Cotton tensor vanishes. Conformal geometry has a number of features which distinguish it from (pseudo-)Riemannian geometry.
One can use the mapping cylinder to construct homotopy colimits: [citation needed] this follows from the general statement that any category with all pushouts and coequalizers has all colimits. That is, given a diagram, replace the maps by cofibrations (using the mapping cylinder) and then take the ordinary pointwise limit (one must take a bit ...