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1 godzinę temu · Definition and basic operations Various complex numbers depicted in the complex plane. A complex number is an expression of the form a + bi, where a and b are real numbers, and i is an abstract symbol, the so-called imaginary unit, whose meaning will be explained further below.For example, 2 + 3i is a complex number. For a complex number a + bi, the real number a is called its real part, and ...
1 godzinę temu · The number π (/ p aɪ /; spelled out as "pi") is a mathematical constant that is the ratio of a circle's circumference to its diameter, approximately equal to 3.14159.The number π appears in many formulae across mathematics and physics.It is an irrational number, meaning that it cannot be expressed exactly as a ratio of two integers, although fractions such as are commonly used to ...
1 dzień temu · Richard Feynman in 1984. In theoretical physics, a Feynman diagram is a pictorial representation of the mathematical expressions describing the behavior and interaction of subatomic particles.The scheme is named after American physicist Richard Feynman, who introduced the diagrams in 1948.The interaction of subatomic particles can be complex and difficult to understand; Feynman diagrams give a ...
1 dzień temu · The United Nations Educational, Scientific and Cultural Organization (UNESCO; pronounced / j uː ˈ n ɛ s k oʊ /) is a specialized agency of the United Nations (UN) with the aim of promoting world peace and security through international cooperation in education, arts, sciences and culture. It has 194 member states and 12 associate members, as well as partners in the non-governmental ...
1 dzień temu · A metal (from Ancient Greek μέταλλον (métallon) 'mine, quarry, metal') is a material that, when polished or fractured, shows a lustrous appearance, and conducts electricity and heat relatively well. These properties are all associated with having electrons available at the Fermi level, as against nonmetallic materials which do not.: Chpt 8 & 19 : Chpt 7 & 8 Metals are typically ...
1 dzień temu · Medical ultrasound includes diagnostic techniques (mainly imaging techniques) using ultrasound, as well as therapeutic applications of ultrasound. In diagnosis, it is used to create an image of internal body structures such as tendons, muscles, joints, blood vessels, and internal organs, to measure some characteristics (e.g. distances and velocities) or to generate an informative audible sound.
