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  2. Curved mirror - Wikipedia

    en.wikipedia.org/wiki/Curved_mirror

    A curved mirror is a mirror with a curved reflecting surface. The surface may be either convex (bulging outward) or concave (recessed inward). Most curved mirrors have surfaces that are shaped like part of a sphere, but other shapes are sometimes used in optical devices. The most common non-spherical type are parabolic reflectors, found in ...

  3. Focal length - Wikipedia

    en.wikipedia.org/wiki/Focal_length

    Focal length. The focal point F and focal length f of a positive (convex) lens, a negative (concave) lens, a concave mirror, and a convex mirror. The focal length of an optical system is a measure of how strongly the system converges or diverges light; it is the inverse of the system's optical power. A positive focal length indicates that a ...

  4. Virtual image - Wikipedia

    en.wikipedia.org/wiki/Virtual_image

    The magnification of the virtual image formed by the plane mirror is 1. Top: The formation of a virtual image using a diverging lens. Bottom: The formation of a virtual image using a convex mirror. In both diagrams, f is the focal point, O is the object, and I is the virtual image, shown in grey. Solid blue lines indicate (real) light rays and ...

  5. Hyperplane separation theorem - Wikipedia

    en.wikipedia.org/wiki/Hyperplane_separation_theorem

    In geometry, the hyperplane separation theorem is a theorem about disjoint convex sets in n-dimensional Euclidean space.There are several rather similar versions. In one version of the theorem, if both these sets are closed and at least one of them is compact, then there is a hyperplane in between them and even two parallel hyperplanes in between them separated by a gap.

  6. Convex optimization - Wikipedia

    en.wikipedia.org/wiki/Convex_optimization

    Convex optimization is a subfield of mathematical optimization that studies the problem of minimizing convex functions over convex sets (or, equivalently, maximizing concave functions over convex sets). Many classes of convex optimization problems admit polynomial-time algorithms, [1] whereas mathematical optimization is in general NP-hard. [2 ...

  7. Cassegrain reflector - Wikipedia

    en.wikipedia.org/wiki/Cassegrain_reflector

    The Cassegrain reflector is a combination of a primary concave mirror and a secondary convex mirror, often used in optical telescopes and radio antennas, the main characteristic being that the optical path folds back onto itself, relative to the optical system's primary mirror entrance aperture. This design puts the focal point at a convenient ...

  8. Convex mirror - Wikipedia

    en.wikipedia.org/?title=Convex_mirror&redirect=no

    Convex mirror. 7 languages. ... Download as PDF; Printable version; From Wikipedia, the free encyclopedia. Redirect page. Redirect to: Curved mirror#Convex mirrors;

  9. History of photographic lens design - Wikipedia

    en.wikipedia.org/wiki/History_of_photographic...

    Early photographic camera lenses (1800–1890) Biconvex (or double convex) lens with aperture stop in front of it. The early photographic experiments of Thomas Wedgwood, Nicéphore Niépce, Henry Fox Talbot, and Louis Daguerre all used simple single-element convex lenses. [2]: 55 These lenses were found lacking.