Jean-Baptiste Joseph Fourier: Perbedaan antara revisi

Jelajahi riwayat secara interaktif

← Revisi sebelumnya

Konten dihapus Konten ditambahkan

VisualTeks wiki

Revisi per 3 Mei 2021 08.09 sunting Adesio2010 (bicara \| kontrib) Peninjau 26.093 suntingan k →Pranala luar ← Revisi sebelumnya		Revisi terkini sejak 8 Januari 2024 08.28 sunting balikkan Wagino 20100516 (bicara \| kontrib) Pemeriksa, Pengurus 161.589 suntingan clean up
(6 revisi perantara oleh 3 pengguna tidak ditampilkan)
Baris 1: {{Infobox orang}} ~~[[Berkas:Fourier.jpg\|jmpl\|Joseph Fourier]]~~ '''Jean -Baptiste Joseph Fourier''' ([[21 Maret]] [[1768]] - [[16 Mei]] [[1830]]) adalah [[matematikawan]] dan [[fisikawan]] [[Prancis]] yang paling dikenal karena mengawali penyelidikan [[deret Fourier]] dan penerapannya pada masalah arus panas. [[Transformasi Fourier]] juga dinamai untuk menghormatinya. == Awal kehidupan == Baris 6 ⟶ 7: == Pekerjaan == Dia pergi bersama [[Napoleon]] dalam ekspedisi Timurnya pada [[1798]], dan dijadikan gubernur Mesir Rendah. Diputus dari Prancis oleh Armada Inggris, dia mengatur sebuah bengkel ~~(''workshop'')~~ di mana pasukan Prancis harus bergantung kepadanya untuk munisi perang. ~~<!--~~ Fourier went with [[Napoleon]] on his Eastern expedition in [[1798]], and was made governor of Lower Egypt. Cut off from France by the English fleet, he organized the workshops on which the French army had to rely for their munitions of war. He also contributed several mathematical papers to the Egyptian Institute which Napoleon founded at [[Cairo]], with a view of weakening English influence in the East. After the British victories and the capitulation of the French under General Menou in [[1801]], Fourier returned to France, and was made prefect of [[Isère]], and it was while there that he made his experiments on the propagation of heat. He moved to Paris in [[1816]]. In [[1822]] he published his ''Théorie analytique de la chaleur'', in which he bases his reasoning on [[Newton's law of cooling]], namely, that the flow of heat between two adjacent molecules is proportional to the extremely small difference of their temperatures. In this work he claims that any functions of a variable, whether continuous or discontinuous, can be expanded in a [[Fourier series\|series of sines]] of multiples of the variable - this result isn't correct at all. But the fact that some discontinuous functions are the sum of infinite series was a breakthrough. The question of determining when a function is the sum of its [[Fourier series]] has been fundamental for centuries. [[Joseph Louis Lagrange\|Lagrange]] had given particular cases of this (false) theorem, and had implied that the method was general, but he had not pursued the subject. [[Johann Peter Gustav Lejeune Dirichlet\|Dirichlet]] was the first to give a satisfactory demonstration of it, with some restrictive conditions. Fourier left an unfinished work on determinate equations which was edited by [[Claude Navier]], and published in [[1831]]; this contains much original matter, in particular there is a demonstration of Fourier's theorem on the position of the roots of an algebraic equation. [[Joseph Louis Lagrange\|Lagrange]] had shown how the roots of an algebraic equation might be separated by means of another equation whose roots were the squares of the differences of the roots of the original equation. [[François Budan de Boislaurent\|François Budan]], in [[1807]] and [[1811]], had enunciated the theorem generally known by the name of Fourier, but the demonstration was not altogether satisfactory. Fourier's proof is the same as that usually given in textbooks on the theory of equations. The final solution of the problem was given in [[1829]] by [[Jacques Charles François Sturm]] ([[1803]]--[[1855]]). Fourier is also credited with the discovery in his essay in [[1824]] that gases in the atmosphere might increase the surface temperature of the Earth. This was the effect that would later be called the [[greenhouse effect]]. He established the concept of planetary energy balance. That planets obtain energy from number of sources that causes temperature increase. Planets also lose energy by [[infrared radiation]] (that Fourier called "chaleur obscure" or "dark heat") with the rate increasing with temperature. Therefore some temperature balance is reached. And atmosphere shifts the balance toward the higher temperatures due to consumption of radiation. Fourier recognized that Earth primarily gets energy from [[Sun radiation]] for which [[atmosphere]] is [[transparent]] and that internal Earth heat doesn't contribute much to the energy balance. However he incorrectly believed that there is a significant contribution of radiation from interplanetary space. Fourier reported on an experiment by M. de Saussure with a black box exposed to the Sun, and in which if thin glass is put on top of the box the temperature inside of the box increases [http://www.wmconnolley.org.uk/sci/fourier_1827/fourier_1827.html#text]. [[Infrared radiation]] was only discovered by [[Frederick Herschel]] 25 years later. Fourier understood that rate of [[infrared radiation]] increases with temperature but exact form of this dependency [[Stefan-Boltzmann law]] (fourth-power law) was only discovered 50 years later. ~~-->~~ Dia meninggal di [[Paris]] dan dimakamkan di [[Pemakaman Père-Lachaise]] dengan sebuah makam yang dihiasi dengan motif Mesir untuk menggambarkan posisinya sebagai sekretaris Institut Kairo. Namanya diabadikan dalam [[Daftar 72 nama di Menara Eiffel]]. Baris 43 ⟶ 36: {{Académie française Kursi 5}} {{lifetime\|1768\|1830\|Fourier, Jean Baptiste Joseph}} {{Authority control}} [[Kategori:Matematikawan Prancis\|Fourier, Jean Baptiste Joseph]]