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  1. Leucippus was a Greek philosopher of the 5th century BCE. He is credited with founding atomism, with his student Democritus. Leucippus divided the world into two entities: atoms, indivisible particles that make up all things, and the void, the nothingness between the atoms. Leucippus's ideas were influential in ancient and Renaissance philosophy.

  2. Eigenvalues and eigenvectors. In linear algebra, it is often important to know which vectors have their directions unchanged by a given linear transformation. An eigenvector ( / ˈaɪɡən -/ EYE-gən-) or characteristic vector is such a vector. Thus an eigenvector of a linear transformation is scaled by a constant factor when the linear ...

  3. In linear algebra, a rotation matrix is a transformation matrix that is used to perform a rotation in Euclidean space. For example, using the convention below, the matrix. rotates points in the xy plane counterclockwise through an angle θ about the origin of a two-dimensional Cartesian coordinate system.

    • Characterizing Properties
    • Useful Relations
    • Second Derivatives
    • Standard Integrals
    • Taylor Series Expressions
    • Infinite Products and Continued Fractions
    • Comparison with Circular Functions
    • Relationship to The Exponential Function
    • Hyperbolic Functions For Complex Numbers
    • See Also

    Hyperbolic cosine

    It can be shown that the area under the curve of the hyperbolic cosine (over a finite interval) is always equal to the arc lengthcorresponding to that interval:

    Hyperbolic tangent

    The hyperbolic tangent is the (unique) solution to the differential equation f ′ = 1 − f 2, with f (0) = 0.

    The hyperbolic functions satisfy many identities, all of them similar in form to the trigonometric identities. In fact, Osborn's rule states that one can convert any trigonometric identity (up to but not including sinhs or implied sinhs of 4th degree) for θ {\displaystyle \theta } , 2 θ {\displaystyle 2\theta } , 3 θ {\displaystyle 3\theta } or θ {...

    Each of the functions sinh and cosh is equal to its second derivative, that is: All functions with this property are linear combinations of sinh and cosh, in particular the exponential functions e x {\displaystyle e^{x}} and e − x {\displaystyle e^{-x}} .

    The following integrals can be proved using hyperbolic substitution: where C is the constant of integration.

    It is possible to express explicitly the Taylor series at zero (or the Laurent series, if the function is not defined at zero) of the above functions. The sum of the sinh and cosh series is the infinite series expression of the exponential function. The following series are followed by a description of a subset of their domain of convergence, where...

    The following expansions are valid in the whole complex plane: 1. sinh ⁡ x = x ∏ n = 1 ∞ ( 1 + x 2 n 2 π 2 ) = x 1 − x 2 2 ⋅ 3 + x 2 − 2 ⋅ 3 x 2 4 ⋅ 5 + x 2 − 4 ⋅ 5 x 2 6 ⋅ 7 + x 2 − ⋱ {\displaystyle \sinh x=x\prod _{n=1}^{\infty }\left(1+{\frac {x^{2}}{n^{2}\pi ^{2}}}\right)={\cfrac {x}{1-{\cfrac {x^{2}}{2\cdot 3+x^{2}-{\cfrac {2\cdot 3x^{2}}{4\cd...

    The hyperbolic functions represent an expansion of trigonometry beyond the circular functions. Both types depend on an argument, either circular angle or hyperbolic angle. Since the area of a circular sector with radius r and angle u (in radians) is r2u/2, it will be equal to u when r = √2. In the diagram, such a circle is tangent to the hyperbola ...

    The decomposition of the exponential function in its even and odd partsgives the identities Additionally,

    Since the exponential function can be defined for any complex argument, we can also extend the definitions of the hyperbolic functions to complex arguments. The functions sinh z and cosh z are then holomorphic. Relationships to ordinary trigonometric functions are given by Euler's formulafor complex numbers: Thus, hyperbolic functions are periodic ...

  4. Enrico Fermi (1901–1954) The Fermi paradox is a conflict between the argument that scale and probability seem to favor intelligent life being common in the universe, and the total lack of evidence of intelligent life having ever arisen anywhere other than on Earth. The first aspect of the Fermi paradox is a function of the scale or the large ...

  5. en.wikipedia.org › wiki › ColosseumColosseum - Wikipedia

    The Colosseum ( / ˌkɒləˈsiːəm / KOL-ə-SEE-əm; Italian: Colosseo [kolosˈsɛːo]) is an elliptical amphitheatre in the centre of the city of Rome, Italy, just east of the Roman Forum. It is the largest ancient amphitheatre ever built, and is still the largest standing amphitheatre in the world, despite its age.

  6. The Great Wall of China ( traditional Chinese: 萬里長城; simplified Chinese: 万里长城; pinyin: Wànlǐ Chángchéng, literally "ten thousand li long wall") is a series of fortifications that were built across the historical northern borders of ancient Chinese states and Imperial China as protection against various nomadic groups from ...