EllipseFor other uses, see Ellipse (disambiguation).Elliptical redirects here, for the exercise machine, see Elliptical trainer. The ellipse and some of its mathematical properties.In mathematics, an ellipse (from the Greek for absence) is a plane algebraic curve where the sum of the distances from any point on the curve to two fixed points is constant. The two fixed points are called foci (plural of focus). An ellipse is a type of conic section: if a conical surface is cut with a plane which does not intersect the cone's base, the intersection of the cone and plane is an ellipse. For a short elementary proof of this, see Dandelin spheres. Algebraically, an ellipse is a curve in the Cartesian plane defined by an equation of the form such that B2 < 4AC, where all of the coefficients are real, and where more than one solution, defining a pair of points (x, y) on the ellipse, exists. An ellipse can be drawn with two pins, a loop of string, and a pencil. The pins are placed at the foci and the pins and pencil are enclosed inside the string. The pencil is placed on the paper inside the string, so the string is taut. The string will form a triangle. If the pencil is moved around so that the string stays taut, the sum of the distances from the pencil to the pins will remain constant, satisfying the definition of an ellipse. The line segment which passes through the foci and terminates on the ellipse is called the major axis. The major axis is along the longest segment that passes through the ellipse. The line which passes through the center (halfway between the foci), at right angles to the major axis, is called the minor axis. A semimajor axis is one half the major axis: the line segment from the center, through a focus, and to the edge of the ellipse. Likewise, the semiminor axis is one half the minor axis. If the two foci coincide, then the ellipse is a circle; in other words, a circle is a special case of an ellipse, one where the eccentricity is zero. An ellipse centred at the origin can be viewed as the image of the unit circle under a linear map associated with a symmetric matrix A = PDPT, D being a diagonal matrix with the eigenvalues of A, both of which are real positive, along the main diagonal, and P being a real unitary matrix having as columns the eigenvectors of A. Then the axes of the ellipse will lie along the eigenvectors of A, and the squares of the lengths of the axes are the inverses of the eigenvalues. ParametrisationThe size of an ellipse is determined by two constants, conventionally denoted a and b. The constant a equals the length of the semimajor axis; the constant b equals the length of the semiminor axis. An ellipse centered at the origin of an x-y coordinate system with its major axis along the x-axis is defined by the equation The derivation of this formula is quite instructive and not overly difficult. The following diagram shows an ellipse demonstrating the Pythagoras equation a² = b² + c² as a special case of the non-parametric equation above (x=0, y=b). The same ellipse is also represented by the parametric equations: which use the trigonometric functions sine and cosine. If an ellipse is not centered at the origin of an x-y coordinate system, but again has its major axis along the x-axis, it may be specified by the equation where (h,k) is the center. A Gauss-mapped form: has normal (cosφ,sinφ). EccentricityThe shape of an ellipse is usually expressed by a number called the eccentricity of the ellipse, conventionally denoted e (not to be confused with the mathematical constant e). The eccentricity is related to a and b by the statement or where c (the linear eccentricity of the ellipse) equals the distance from the center to either focus The eccentricity is a positive number less than 1, or 0 in the case of a circle. The greater the eccentricity is, the larger the ratio of a to b is, and therefore the more elongated the ellipse is. The ellipse shown in the image below has an eccentricity of approximately 0.8733. The distance between the foci is 2ae. Semi-latus rectum and polar coordinatesThe semi-latus rectum of an ellipse, usually denoted (lowercase L), is the distance from a focus of the ellipse to the ellipse itself, measured along a line perpendicular to the major axis. It is related to and (the ellipse's semi-axes) by the formula or, if using the eccentricity, . In polar coordinates, an ellipse with one focus at the origin and the other on the negative x-axis is given by the equation An ellipse can also be thought of as a projection of a circle: a circle on a plane at angle φ to the horizontal projected vertically onto a horizontal plane gives an ellipse of eccentricity sin φ, provided φ is not 90°. AreaThe area enclosed by an ellipse is , where π is Archimedes' constant. CircumferenceThe circumference of an ellipse is 4aE(e), where the function E is the complete elliptic integral of the second kind. The exact infinite series is: A good approximation is Ramanujan's: which can also be written as: More generally, the arc length of a portion of the circumference, as a function of the angle subtended, is given by an incomplete elliptic integral. The inverse function, the angle subtended as a function of the arc length, is given by the elliptic functions. Stretching and ProjectionAn ellipse may be uniformly stretched along any axis, in or out of the plane of the ellipse, and it will still be an ellipse. The stretched ellipse will have different properties (perhaps changed eccentricity and semi-major axis length, for instance), but it will still be an ellipse (or a degenerate ellipse: a circle or a line). Similarly, any oblique projection onto a plane results in a conic section. If the projection is a closed curve on the plane, then the curve is an ellipse or a degenerate ellipse. Reflection propertyAssume an elliptic mirror with a light source at one of the foci. Then all rays are reflected to a single point — the second focus. Since no other curve has such a property, it can be used as an alternative definition of an ellipse. Ellipses in physicsIndian astronomer Aryabhata discovered that the orbits of the planets around the sun are ellipses in 499, which he described in his book, the Aryabhatiya [1]. In the 17th century, Johannes Kepler explained that the orbits along which the planets travel around the Sun are ellipses, which is Kepler's first law. Later, Isaac Newton explained this as a corollary of his law of universal gravitation. More generally, in the gravitational two-body problem, if the two bodies are bound to each other (i.e., the total energy is negative), their orbits are similar ellipses with the common barycenter being one of the foci of each ellipse. Interestingly, the orbit of either body in the reference frame of the other is also an ellipse, with the other body at one focus. The general solution for a harmonic oscillator in two or more dimensions is also an ellipse, but this time with the origin of the force located at the center of the ellipse. Albert Einstein also used the ellipse to prove his theory of relativity by using an elliptical shaped mass. Einstein's contributions to modern physics may not have been discovered if it were not for ellipses. Ellipses in computer graphicsDrawing an ellipse is a common graphics primitive in standard display libraries, such as the QuickDraw and GDI interfaces on the Macintosh and Windows systems. Often such libraries are limited and can only draw an ellipse with either the major axis or the minor axis horizontal. Jack Bresenham at IBM is most famous for the invention of 2D drawing primitives, including line and circle drawing, using only fast integer operations such as addition and branch on carry bit. An efficient generalization to draw ellipses was invented in 1984 by Jerry Van Aken (IEEE CG&A, Sept. 1984). A more challenging task is to perform these drawing operations with antialiasing, to create a smooth-looking curve. The curve drawing algorithms of Xiaolin Wu (SIGGRAPH 91) are an example. This page about Elliptical includes information from a Wikipedia article. 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The curve drawing algorithms of Xiaolin Wu (SIGGRAPH 91) are an example. See the appropriate section for further details. A more challenging task is to perform these drawing operations with antialiasing, to create a smooth-looking curve. Additionally food contains water and dietary fiber. 1984). Micronutrients are the minerals and vitamins. An efficient generalization to draw ellipses was invented in 1984 by Jerry Van Aken (IEEE CG&A, Sept. Macronutrients means fat, protein, and carbohydrates. Jack Bresenham at IBM is most famous for the invention of 2D drawing primitives, including line and circle drawing, using only fast integer operations such as addition and branch on carry bit. Nutrients in food are grouped into several categories. Often such libraries are limited and can only draw an ellipse with either the major axis or the minor axis horizontal. This has led to the emergence of a counterculture with a preference for organic and local food. Drawing an ellipse is a common graphics primitive in standard display libraries, such as the QuickDraw and GDI interfaces on the Macintosh and Windows systems. Further concerns about the impact of industrial farming on animal welfare, human health and the environment are also having an effect on contemporary human dietary habits. Einstein's contributions to modern physics may not have been discovered if it were not for ellipses. More recently, dietary habits have been influenced by the concerns that some people have about the chronic impact on health that arise through the consumption of genetically modified food. Albert Einstein also used the ellipse to prove his theory of relativity by using an elliptical shaped mass. Physicians and alternative medicine practitioners may recommend changes to diet as part of their recommendations for treatment. The general solution for a harmonic oscillator in two or more dimensions is also an ellipse, but this time with the origin of the force located at the center of the ellipse. Contemporary changes to work, family and exercise patterns, together with concerns about the effect of nutrition and overeating on human health and mortality are all having an effect on traditional eating habits. Interestingly, the orbit of either body in the reference frame of the other is also an ellipse, with the other body at one focus. The nutrient content of diets in industrialised countries contain more animal fat, sugar, energy, alcohol and less dietary fiber, carbohydrates and antioxidants. More generally, in the gravitational two-body problem, if the two bodies are bound to each other (i.e., the total energy is negative), their orbits are similar ellipses with the common barycenter being one of the foci of each ellipse. Additionally, many people choose to forgo food from animal sources to varying degrees; see vegetarianism, veganism, fruitarianism, living foods diet, and raw foodism. Later, Isaac Newton explained this as a corollary of his law of universal gravitation. Some believe that this is the underlying rationale behind some traditional religious dietary requirements. In the 17th century, Johannes Kepler explained that the orbits along which the planets travel around the Sun are ellipses, which is Kepler's first law. Traditionally humans have learned to avoid foods that induce acute illness. Indian astronomer Aryabhata discovered that the orbits of the planets around the sun are ellipses in 499, which he described in his book, the Aryabhatiya [1]. Concerns about foodborne illness have long influenced diet. Since no other curve has such a property, it can be used as an alternative definition of an ellipse. For example:. Then all rays are reflected to a single point — the second focus. Dietary habits play a significant role in the health and mortality of all humans. Assume an elliptic mirror with a light source at one of the foci. The syndrome has a strong inherited component; a family history of these diseases can be indicative of the atopic syndrome. If the projection is a closed curve on the plane, then the curve is an ellipse or a degenerate ellipse. Food allergy is thought to develop easier in patients with the atopic syndrome, a very common combination of diseases: allergic rhinitis and conjunctivitis, eczema and asthma. Similarly, any oblique projection onto a plane results in a conic section. Initial treatment is with epinephrine (adrenaline), often carried by known patients in the form of an Epi-pen. The stretched ellipse will have different properties (perhaps changed eccentricity and semi-major axis length, for instance), but it will still be an ellipse (or a degenerate ellipse: a circle or a line). An allergen associated with this type of reaction is peanut, although latex products can induce similar reactions. An ellipse may be uniformly stretched along any axis, in or out of the plane of the ellipse, and it will still be an ellipse. This is a medical emergency. The inverse function, the angle subtended as a function of the arc length, is given by the elliptic functions. Rarely, food allergy can lead to anaphylactic shock: hypotension (low blood pressure) and loss of consciousness. More generally, the arc length of a portion of the circumference, as a function of the angle subtended, is given by an incomplete elliptic integral. The digestive complaints usually develop within half an hour of ingesting the allergen. which can also be written as:. Most patients present with diarrhea after ingesting certain foodstuffs, skin symptoms (rashes), bloating, vomiting and regurgitation. A good approximation is Ramanujan's:. In theory, any food may provoke a reaction, however, this most commonly involves gluten, corn, shellfish (mollusks), peanuts, and soy. The exact infinite series is:. For instance, tiny amounts of food in the air, too minute to be smelled, have been known to provoke lethal reactions in sufficiently sensitive individuals. The circumference of an ellipse is 4aE(e), where the function E is the complete elliptic integral of the second kind. The amount of the food substance required to provoke a reaction in a susceptible individual can be minute. The area enclosed by an ellipse is , where π is Archimedes' constant. Some people have food allergies or sensitivities to foods which are otherwise wholesome to the majority of people. An ellipse can also be thought of as a projection of a circle: a circle on a plane at angle φ to the horizontal projected vertically onto a horizontal plane gives an ellipse of eccentricity sin φ, provided φ is not 90°. HACCP is well suited to identifying and controlling these potential food safety risks. In polar coordinates, an ellipse with one focus at the origin and the other on the negative x-axis is given by the equation. Understanding of the causes of food-borne-illnesses and more systematic techniques for their elimination has led to the development of commercial systems such as HACCP which can, if properly implemented, identify and eliminate many, but not all, possible risks. It is related to and (the ellipse's semi-axes) by the formula or, if using the eccentricity, . It is possible for certain types of food to become contaminated if stored or presented in an unsafe container, such as a ceramic pot with lead-based glaze. The semi-latus rectum of an ellipse, usually denoted (lowercase L), is the distance from a focus of the ellipse to the ellipse itself, measured along a line perpendicular to the major axis. For example, pests (or their feces), hairs, cigarette butts, wood chips, metal shards, plasters etc. The distance between the foci is 2ae. Food can also be adulterated by a very wide range of articles (known as 'foreign bodies') during farming, manufacture, cooking, packaging, distribution or sale. The ellipse shown in the image below has an eccentricity of approximately 0.8733. Less commonly, acute adverse reactions can also occur if chemical contamination of food occurs, for example from improper storage, or use of non-food grade soaps and disinfectants. The greater the eccentricity is, the larger the ratio of a to b is, and therefore the more elongated the ellipse is. The two most common factors leading to cases of bacterial foodborne illness are cross-contamination of ready-to-eat food from other uncooked foods and improper temperature control. The eccentricity is a positive number less than 1, or 0 in the case of a circle. This was further underpinned by the work of Justus von Liebig whose work led to the development of modern food storage and food preservation methods. or where c (the linear eccentricity of the ellipse) equals the distance from the center to either focus. Discovery of techniques for killing bacteria using heat and other microbiological studies by scientists such as Louis Pasteur contributed to the modern sanitation standards that we enjoy today. The eccentricity is related to a and b by the statement. The sale of rancid, contaminated or adulterated food was commonplace until introduction of hygiene, refrigeration, and vermin controls in the 19th century. The shape of an ellipse is usually expressed by a number called the eccentricity of the ellipse, conventionally denoted e (not to be confused with the mathematical constant e). In the Middle Ages all Royal Courts had food tasters. has normal (cosφ,sinφ). Murder by food poisoning was used during the Roman Empire. A Gauss-mapped form:. Food poisoning has been recognised as a disease of man since as early as Hippocrates. where (h,k) is the center. Foodborne illness, commonly called "food poisoning," is caused by bacteria, toxins, viruses and prions. If an ellipse is not centered at the origin of an x-y coordinate system, but again has its major axis along the x-axis, it may be specified by the equation. International efforts to distribute food to the neediest countries are co-ordinated by the World Food Programme. which use the trigonometric functions sine and cosine. Its provision, or threatened withdrawal, is sometimes used as a political tool to influence the politics of the destination country. The same ellipse is also represented by the parametric equations:. Conversely, badly managed food aid can like problems by disrupting local markets, depressing crop prices and discouraging food production. The following diagram shows an ellipse demonstrating the Pythagoras equation a² = b² + c² as a special case of the non-parametric equation above (x=0, y=b). Food aid can benefit people suffering from a shortage of food. The derivation of this formula is quite instructive and not overly difficult. Food deprivation is regarded as a deficit need in Maslow's hierarchy of needs and is measured using famine scales. An ellipse centered at the origin of an x-y coordinate system with its major axis along the x-axis is defined by the equation. Rationing is sometimes used to distribute food in times of shortage, most notably during times of war. The constant a equals the length of the semimajor axis; the constant b equals the length of the semiminor axis. In 2003 it was estimated that each year, 40 million people die of hunger worldwide. The size of an ellipse is determined by two constants, conventionally denoted a and b. This can have a devastating and widespread effect on human health and mortality. . This is often connected with famine, which involves the absence of food in entire communities.
Likewise, the semiminor axis is one half the minor axis. The supermarket giants wield great purchasing power over farmers and processors, and strong influence over consumers. A semimajor axis is one half the major axis: the line segment from the center, through a focus, and to the edge of the ellipse. Unlike food processors, food retailing is a two-tier market in which a small number of very large companies control a large proportion of supermarkets. The line which passes through the center (halfway between the foci), at right angles to the major axis, is called the minor axis. This was sometimes known as 'pile it high' In the latter part of the 20th century, this has been further revolutionised by the development of vast warehouse sized out-of-town supermarkets, selling an extraordinarily wide range of food from around the world. The major axis is along the longest segment that passes through the ellipse. Supermarkets brought with them a self service approach to shopping using shopping carts (or Trollies in Commonwealth English) and were able to offer quality food at lower cost, through economies of scale and reduced staffing costs. The line segment which passes through the foci and terminates on the ellipse is called the major axis. In the 20th century supermarkets were born. If the pencil is moved around so that the string stays taut, the sum of the distances from the pencil to the pins will remain constant, satisfying the definition of an ellipse. Typically early grocery shops would be counter-based shops, in which purchasers told the shop-keeper what they wanted, so that the shop-keeper could get it for them. The string will form a triangle. With the onset of industrialisation, and the development of the food processing industry, a wider range of food could be sold and distributed in distant locations. The pencil is placed on the paper inside the string, so the string is taut. Here food was sold to grocers for sale in their local shops for purchase by local people. The pins are placed at the foci and the pins and pencil are enclosed inside the string. The sale of surplus food traditionally took place once a week when farmers took their wares on market day, into the local village market place. An ellipse can be drawn with two pins, a loop of string, and a pencil. Where trade barriers are raised on the disputed grounds of public health and safety, the WTO refer the dispute to the Codex Alimentarius Commission, which was founded in 1962 by the United Nations Food and Agriculture Organization and the World Health Organization. such that B2 < 4AC, where all of the coefficients are real, and where more than one solution, defining a pair of points (x, y) on the ellipse, exists. This is underpinned by the WTO enforcement of agricultural subsidy, tariffs, import quotas and settlement of trade disputes that cannot be bilaterally resolved. Algebraically, an ellipse is a curve in the Cartesian plane defined by an equation of the form. In 1994 trade liberalisation began when over 100 countries became signatories to the Uruguay Round of the General Agreement on Tariffs and Trade which included an agreement to reduce subsidies paid to farmers. For a short elementary proof of this, see Dandelin spheres. Some countries are now economically dependent on food exports, which in some cases account for over 80% of all exports. An ellipse is a type of conic section: if a conical surface is cut with a plane which does not intersect the cone's base, the intersection of the cone and plane is an ellipse. Between 1961 and 1999 there has been a 400% increase in worldwide food exports. The two fixed points are called foci (plural of focus). The variety and availability of food is no longer restricted by the diversity of locally grown food or the limitations of the local growing season. In mathematics, an ellipse (from the Greek for absence) is a plane algebraic curve where the sum of the distances from any point on the curve to two fixed points is constant. Food is now traded on a global basis. Elliptical redirects here, for the exercise machine, see Elliptical trainer.. At the start of the 21st century, a two-tier structure has arisen, with a few international food processing giants controlling a wide range of well known food brands; with a populous number of small local or national food processing companies. It brought the advantages of pre-prepared time saving food to the bulk of ordinary people who did not employ domestic servants. This development took advantage of new mass markets and emerging new technology, such as milling, preservation, packaging and labelling and transportation. During the industrialisation era in the 19th century, food manufacturing arose. An early processed food product was cheese. Early food processing mainly involved salting, curing, curdling, drying, pickling and smoking. Early food processing techniques were limited by the available food preservation, packaging and transportation. The preparation of animal-based food will usually involve slaughter, evisceration, hanging, portioning and rendering. Most food preparation takes place in a kitchen. It may also involve mixing, heating or cooling, pressure cooking, fermentation, or combination with other food. At the simplest level this may involve washing, cutting, trimming or adding other foods or ingredients, such as spices. While some food can be eaten without preparation, many foods undergo some form of preparation for reasons of safety, palatability, or flavor. Food for livestock is fodder and traditionally comprises hay or grain. the World Trade Organization and Common Agricultural Policy, national government policy or law and war. Major influences on food production are international policy, e.g. This approach - which is partly fuelled by consumer demand - encourages biodiversity, local self-reliance and Organic farming methods. More recently, there has been a growing trend towards more Sustainable agricultural practices. Developed tools have been combined with the use of pesticides to promote high crop yields and to combat insects or mammals which reduce yield. The techniques include a reliance on mechanized tools, from the threshing machine and seed drill, to the tractor and combine. These techniques aim to maximize the amount of food produced while minimizing the cost. In the modern era in developed nations, food supply is increasingly dependent upon agriculture, industrial farming, aquaculture and fish farming techniques. Food is traditionally obtained through farming, ranching, and fishing, with hunting, foraging and other methods of subsistence locally important for some populations, but minor for others. Food eaten in smaller quantities between the culturally normative meals is regarded as snack food. In societies where the availability of food has risen above subsistence levels and beyond staple foods, meals are also sold pre-prepared for immediate consumption in restaurants and other similar retail premises. This diversity can be attributed to a number of local factors, including climate, ecology, economy, cultural traditions and industrialisation. The number of meals consumed by individuals in a day, their size, composition, when and how they are prepared and eaten varies greatly around the world. A meal can be used as means for feeding a single individual or shared and eaten simultaneously by two or more people. Often named and patterned, meals play a role in an important social occasion, such as the celebration of many key cultural and religious festivals. A portion of food or the act of eating a portion of food is considered a meal. The types of food consumed, and the way in which they are prepared, have varied widely by time, location, and culture. This led to a variety of important historical consequences, such as increased population, the development of cities, and the wider spread of infectious diseases. At least ten thousand years ago, humans developed agriculture, which has altered the kind of food people eat. Additionally, it is believed that humans have used fire to prepare food prior to eating since their divergence from Homo erectus, possibly even earlier. This involves combining stationary plant and fungal food sources (such as fruits, grains, roots, and mushrooms) with mobile animals which must be hunted and killed in order to be consumed. Evidence suggests that early humans employed hunter-gatherer techniques as their primary method of food collection. Humans are commonly believed to be omnivorous animals that can consume both plant and animal products. Links to official legal definitions of food:. Western food law defines four categories of object as food:. . In English, the term food is often used metaphorically or figuratively, as in food for thought. The study of food is called food science. Many countries have a recognizable cuisine, a specific set of cooking traditions and practices. Food is the main source of energy and of nutrition for animals, and is usually of animal or plant origin. Food is any substance that can be consumed, including liquid drinks. Obesity, a serious problem in the western world, leads to higher chances of developing heart disease, diabetes, and many other diseases. Kwashiorkor and marasmus are childhood disorders caused by lack of dietary protein. The consumption of each may affect the absorption of the others. Calcium, Vitamin D and Phosphorus are inter-related. Vitamin C deficiency results in scurvy;. In 2003 it was estimated that vitamin A deficiency causes blindness in up to 500,000 children each year;. 13% of the world's population suffer from Iodine deficiency;. They often affect people with a negative body image;. Eating disorders are a group of mental disorders that interfere with normal food consumption. Sausage. Sauce. Salad. Sandwiches. Processed meats. Pizza. Pie. Pasta. Jam and Jelly. Functional food. French fries, Chips. Ice cream. Dessert is a course, usually sweet, and generally served after the main course, e.g. Cheese is a curdled milk product, of which many varieties exist. Cakes and cookies. Bread is a staple food for many nations, being made of risen dough of wheat or other cereals. Drinks: beer, juice, soft drink, squash, wine. Blue Green Algae (cyanobacteria). Water, including mineral water and spring (water). Seaweed, which is a protist. Mushrooms, which are a type of fungi. Yeast, which is a type of fungi (and an essential ingredient in bread and beer). Salt. Game, this includes all animals hunted for food. Snails. Seafood, including finfish such as salmon and tilapia, and shellfish such as mollusks and crustaceans. Poultry, including chicken, turkey, duck, goose, pigeon or dove, ostrich, emu, guinea fowl, pheasant, quail. Offal, including blood. cannibalism). Meat, including beef, frogs' legs, goat, horse, kangaroo, lamb, mutton, pork, veal, rodents, human (i.e. Insects, including honey. Eggs, including roe and caviar. Dairy products, including milk. Herbs and spices (see also list of herbs and spices). Fruits (see also list of fruits). Fruit vegetables, including pumpkin, okra, and eggplant. inflorescence vegetables, including globe artichokes, broccoli, and daylilies. Stem vegetables, including bamboo shoots, nopales, and asparagus. Sea vegetables, including dulse, kombu, and dabberlocks. Leaf vegetables, including amaranth, spinach, and kale. Root vegetables, including potatoes, cassava, and turnips. Vegetables (see also list of vegetables)
Nuts, including coconuts, almonds, and pine nuts. Legumes, including beans, peas, and lentils. Cereals from non-grasses, including buckwheat, amaranth, and quinoa. Cereals from grasses, including barley, maize, oats, rice, rye, and wheat. Seeds
articles and substances used as an ingredient or component in the preparation of food. chewing gum;. water and other drinks;. any substance or product, whether processed, partially processed or unprocessed, intended to be, or reasonably expected to be ingested by humans whether of nutritional value or not;. |