Trigonometri,\u00a0\u00fc\u00e7genin a\u00e7\u0131lar\u0131 ve kenarlar\u0131\u00a0aras\u0131ndaki ba\u011f\u0131nt\u0131lar\u0131 inceleyen bir matematik dal\u0131d\u0131r. Frans\u0131zca bir kelime olan trigonometri, Yunanca\u00a0\u00fc\u00e7gen m\u00e2n\u00e2s\u0131na gelen trigonas ile \u00f6l\u00e7\u00fc m\u00e2n\u00e2s\u0131na gelen metron kelimelerinin birle\u015fimidir. \u00dc\u00e7gen\u00a0\u00f6l\u00e7\u00fcmleriyle me\u015fgul olan trigonometri, geometrinin ilk geli\u015fen dallar\u0131ndan biridir. Bilinen \u00fc\u00e7gen, y\u00e2ni\u00a0d\u00fczlem \u00fc\u00e7gendeki ba\u011f\u0131nt\u0131lar\u0131 inceleyen trigonometriye d\u00fczlem trigonometri, k\u00fcre y\u00fczeyi \u00fczerine \u00e7izilen\u00a0\u00fc\u00e7genlerdeki ba\u011f\u0131nt\u0131lar\u0131 inceleyen trigonometriye k\u00fcrev\u00ee trigonometri denir.<\/p>\n
Trigonometrinin ba\u015flang\u0131c\u0131 M\u0131s\u0131r<\/strong> ve Mezopotamya<\/strong>\u2019ya dayanmaktad\u0131r. Matemati\u011fin do\u011frudan do\u011fruya astronomiden \u00e7\u0131km\u0131\u015f bir kolu olan Trigonometri<\/strong>‘<\/i>nin baz\u0131 \u00f6geleri, daha Babilliler ve Eski M\u0131s\u0131rl\u0131lar d\u00f6neminde biliniyor, S\u00fcmerli astronomlar ilk kez bir \u00e7emberi 360 e\u015fit par\u00e7aya b\u00f6lerek a\u00e7\u0131 \u00f6l\u00e7\u00fcm\u00fcn\u00fc yapt\u0131lar. D\u00e2irenin 360 dereceye b\u00f6l\u00fcm\u00fc\u00a0bu zamandan kalmad\u0131r. Astronomideki geli\u015fmelere paralel olarak k\u00fcrev\u00ee trigonometri de geli\u015fmi\u015ftir.\u00a0M.\u00d6. 4. y\u00fczy\u0131lda Hindular\u0131n trigonometriyi astronomide kulland\u0131klar\u0131 bilinmektedir.<\/p>\n Eski Yunanlar Menelaos\u2019un k\u00fcresel geometrisi arac\u0131l\u0131\u011f\u0131yla, bir daire i\u00e7ine \u00e7izilebilen d\u00f6rtgenden yola \u00e7\u0131karak daire yaylar\u0131n\u0131n kiri\u015flerinin de\u011ferlerini veren \u00e7izgiler olu\u015fturuyorlard\u0131. Daha sonra Araplar, yay kiri\u015flerinin yerine sin\u00fcsleri koyup; tanjant, kotanjant, sekant, kosekant<\/strong> kavramlar\u0131n\u0131 geli\u015ftirdiler<\/p>\n \u0130skenderiyeli\u00a0Claudius Ptolemy<\/strong>, Almagest adl\u0131 eserinde (M.\u00d6. 150) trigonometrik oranlara yer vermi\u015ftir.\u00a0Araplar trigonometride \u00f6nemli geli\u015fmeler kaydetmi\u015flerdir. El-Battan\u00ee<\/strong> (850-929) k\u00fcrev\u00ee \u00fc\u00e7gende\u00a0kosin\u00fcs teorisini ortaya koymu\u015ftur. Eb\u00fc\u2019l-Vef\u00e2<\/strong> (940-998) k\u00fcrev\u00ee \u00fc\u00e7gende sin\u00fcs teoremini bulmu\u015f, Bat\u0131da Nas\u00eer\u00fcddin T\u00fbs\u00ee\u2019den b\u00fcy\u00fck \u00f6l\u00e7\u00fcde yararlanan Regiomontanus<\/strong>\u2019un \u00fc\u00e7gen \u00fcst\u00fcne adl\u0131 eseriyle ger\u00e7ek trigonometri do\u011fmu\u015f oldu. Fran\u00e7ois Vi\u00e8te<\/strong> ve Simon Stevin<\/strong>, hesaplarda ondal\u0131k say\u0131lardan yararland\u0131lar. John Napier<\/strong><\/a> logaritmay\u0131 i\u015fe katt\u0131. Isaac Newton<\/strong><\/a> ve \u00f6\u011frencileri trigonometri i\u015flevlerinin ve logaritmalar\u0131n\u0131n hesab\u0131na tam serileri uygulad\u0131lar. Daha sonra da Leonhard Euler<\/a><\/strong>, birim olarak trigonometrik cetvelin yar\u0131\u00e7ap\u0131n\u0131 alarak, modern trigonometrinin temellerini att\u0131<\/p>\n
\ntrigonometrik cetvel haz\u0131rlam\u0131\u015ft\u0131r. Nas\u00eereddin-i T\u00fbs\u00ee<\/strong> (1201-1247) ilk def\u00e2 d\u00fczlem ve k\u00fcrev\u00ee\u00a0trigonometriyi, astronomiden ay\u0131rarak matemati\u011fin bir b\u00f6l\u00fcm\u00fc olarak ele al\u0131p, bu konuda ilk eseri veren\u00a0matematik\u00e7i olmu\u015ftur.<\/p>\n