[br]Усмерена дуж одређена је уређеним паром тачака, при чему је прва координата тог пара почетак, а друга крај усмерене дужи.[br]Усмерену дуж чији је почетак тачка А, а крај тачка В, oзначавамо са [img]data:image/png;base64,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[/img][br]И на сликама усмерење истичемо стрелицама.[br][br]

Две усмерене дужи [img]data:image/png;base64,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[/img] и [img]data:image/png;base64,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[/img] су [u]истог правца[/u] ако важи [img]data:image/png;base64,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[/img] и то записујемо са: [br][img]data:image/png;base64,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[/img]

Две усмерене дужи [img]data:image/png;base64,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[/img] и [img]data:image/png;base64,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[/img] су [u]истог смера[/u] [img]data:image/png;base64,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[/img] ако важи [img]data:image/png;base64,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[/img] и постоји раван номална на правце усмерених дужи таква да се полуправе [AB) и [CD) налазе са исте стране те равни. [br][br]Очигледно, за усмерене дужи на претходној слици таква раван не постоји, иако су истог правца.[br][br]Но, у следећој ситуацији таква раван постоји:

Две усмерене дужи [img]data:image/png;base64,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[/img] и [img]data:image/png;base64,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[/img] су [u]различитог смера[/u] [img]data:image/png;base64,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[/img] ако важи [img]data:image/png;base64,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[/img] и не постоји раван номална на правце усмерених дужи таква да се полуправе [AB) и [CD) налазе са исте стране те равни.

Усмерене дужи су једнаке, [img]data:image/png;base64,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[/img], ако важи: [img]data:image/png;base64,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[/img] и [img]data:image/png;base64,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[/img]

[color=#a64d79][b][u][size=200]Т1[/size][/u][/b][/color] Једнакост усмерених дужи је рефлексивна, симетрична и транзитивна релација тј. важи[br][list=1][*][img]data:image/png;base64,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[/img][/*][*][img]data:image/png;base64,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[/img][/*][*][img]data:image/png;base64,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[/img][/*][/list]Дакле, у питању је уобичајена релација еквиваленције. [br]Такође важе и:[br][br] 4. [img]data:image/png;base64,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[/img][br] 5. [img]data:image/png;base64,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[/img]

[color=#a64d79][b][u][size=200]Т2[/size][/u][/b][/color] Нека су A, B, C, D четири различите неколинеарне тачке. [br][list=1][*]Ако је [img]data:image/png;base64,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[/img], онда је ABDС паралелограм.[/*][*]Ако је ABCD паралелограм, онда је [img]data:image/png;base64,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[/img] и [img]data:image/png;base64,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[/img][/*][*]Ако је [img]data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAFoAAAAVCAYAAADGpvm7AAACgUlEQVRYhe1Z0a3kIAykBddAC/RACdRAC+kgHaQDKqCCNJAG6MA9zH08mZclJsve6ZJI74200gqyBA/jsZM1uAClFIQQwMxX3O4RaGM2V904pQTn3I8iex+zAQBjzGUf7/3d8QO4PubLFV1KueqWt2Mf8yVE/3r0hR790/FL9EUYIjrGCGMM1nVV59d17RYCay1ijI+2DW3fRATvPVJKQ2uklL6KXlMEl2X5use7BfYk9ogGgGVZYIxBjLGOMXMdd84NbfgObNtWRbEfCyEcYmrBzPW6eZ6roOZ5rmPAANHOubpQzrl7XUoJxhhVAc45GPNclxKiNUJFpT1lCzfa/F6cp9GnlGCtraqW09EwTROMMWr79nSic84wxtQ01+ZCCIc5EdeZ4gXd6JkZRISU0hDRzjkQ0WFcfjuymbsgItm27TBXSjnYisBa2xVXiy7R0zTVp7gRottTZ2aklGpRGS2G4m2ffM5qxwjEHs5ia0V0pnR1DW1QPEsCeKfKXtdBRKe+/hScvRqQ2Np56cRGuxKVaO/9y8JCfG8zosK9srZtq3aipeRT8C5bRbmtyD6xDUAhWhZu0/GM6F7qSRCj6XUHRCS9zOspV7J2FC9XMnM9qU/evBGR2if30u4MV3u0tGdaDWHmaoHt/KdxvRAtQWqprhUE4NtWpmk6zH1aMO4AEakdBfB9CFrb99dEl1JARF2v6qWKPPlpReFds383zh5U3vXIkvktmBnOuaPVyBchRUtD2ZBm/nLq+ywYfXy9GyKSvWJzzpULLUvb3+7f40gDoPFkALy8DGl73rZ12/8d1fNTay1CCP/c3/5P5JxBROreY4xDe1+W5VDTvPequP4AbxXb+Viq9MUAAAAASUVORK5CYII=[/img] онда је и [img]data:image/png;base64,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[/img][/*][/list]

Скуп свих усмерених дужи које су међусобно једнаке називамо ВЕКТОР.[br][br]Сваки вектор садржи бесконачно много усмерених дужи, али је довољно да знамо само једну од њих![br][br]Усмерене дужи једног истог вектора поклапају се по [br]1. интензитету (дужини)[br]2. смеру (а самим тим и правцу)[br][br]Два вектора могу имати исти правац, али не морају бити истог смера нити истог интензитета![br][br]Направите разлику између вектора и усмерених дужи![br][br]Усмерене дужи [img]data:image/png;base64,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[/img] и [img]data:image/png;base64,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[/img] са горње слике представљају један исти вектор [img]data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAA0AAAASCAYAAACAa1QyAAAAxUlEQVQokbXSUY0EMQgGYCygoRbwMBLQMFKqBCFjAAM4wMO/TyXT4zZ7t9ltMi9kvrY/lPDGolc/RARUFZn5dwQAZgYRKdgQET39juP4/0kR8eVMLcJHkLtDVbfwZgZm/h25O5h5Cz3nBBFhjNFRZoKZMcbYQl/XBSLCeZ4drR3NbLvuQvd6oTEGiHpf1mbu3tF94vclIlsTCq0r/ESrrqodRURDmVmtn3N2tDIxMzITEVHzWej+nAq5ezVDVWtOIlK11YwHG/YC+4ZCozUAAAAASUVORK5CYII=[/img].

[color=#a64d79][b][u][size=200]Т3[/size][/u][/b][/color] За било који вектор [img]data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAA0AAAASCAYAAACAa1QyAAAAxUlEQVQokbXSUY0EMQgGYCygoRbwMBLQMFKqBCFjAAM4wMO/TyXT4zZ7t9ltMi9kvrY/lPDGolc/RARUFZn5dwQAZgYRKdgQET39juP4/0kR8eVMLcJHkLtDVbfwZgZm/h25O5h5Cz3nBBFhjNFRZoKZMcbYQl/XBSLCeZ4drR3NbLvuQvd6oTEGiHpf1mbu3tF94vclIlsTCq0r/ESrrqodRURDmVmtn3N2tDIxMzITEVHzWej+nAq5ezVDVWtOIlK11YwHG/YC+4ZCozUAAAAASUVORK5CYII=[/img] и неку фиксирану тачку О постоји јединствена тачка А таква да је [br] [img]data:image/png;base64,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[/img].[br][br]Дакле, приликом избора усмерене дужи која ће представљати вектор сасвим је свеједно у којој тачки ће бити њен почетак.[br][br]Такође, на овај начин се успоставља обострано једнозначно пресликавање између скупа свих тачака и скупа свих вектора. Довољно је фиксирати почетак О.[br]Вектор [img]data:image/png;base64,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[/img] зовемо и вектором положоја тачке А у односу на тачку О.

Два вектора су истог правца ако су такве усмерене дужи које их представљају.[br]Векторе истог правца зовемо КОЛИНЕАРНИМ.[br][br]Два вектора су истог интензитета ако су такве усмерене дужи које их представљају.[br][br]Векотори су истог смера ако су истог смера усмерене дужи које их представљају.